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Number

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Real number systems (rational and irrational numbers)

Subtopic

Real number systems (rational and irrational numbers) under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If a number is denoted as x∈Z+x \in \mathbb{Z}^+, what does this mean?

    A.

    xx is a negative integer

    B.

    xx is a positive integer

    C.

    xx is any rational number

    D.

    xx is zero

  2. 2.

    Which of these decimals is the same as 1/21/2?

    A.

    0.050.05

    B.

    0.50.5

    C.

    0.20.2

    D.

    0.120.12

  3. 3.

    Evaluate ∣−3×4∣|-3 \times 4|.

    A.

    −12-12

    B.

    1212

    C.

    77

    D.

    −7-7

Download the worksheet for Number - Real number systems (rational and irrational numbers) to practice offline. It includes additional chapter-level practice questions.

Set theory and Venn diagrams

Subtopic

Set theory and Venn diagrams under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    What is the complement of the universal set, U′U'?

    A.

    UU

    B.

    {0}\{0\}

    C.

    ∅\emptyset

    D.

    All real numbers

  2. 2.

    If A={1,2,3}A = \{1, 2, 3\} and B={1,2,3,4}B = \{1, 2, 3, 4\}, which of the following is the set B∖AB \setminus A (elements in BB not in AA)?

    A.

    {4}\{4\}

    B.

    {1,2,3}\{1, 2, 3\}

    C.

    {1,2,3,4}\{1, 2, 3, 4\}

    D.

    ∅\emptyset

  3. 3.

    What is the cardinality of the set Z={0}Z = \{0\}?

    A.

    0

    B.

    1

    C.

    ∅\emptyset

    D.

    Undefined

Download the worksheet for Number - Set theory and Venn diagrams to practice offline. It includes additional chapter-level practice questions.

Laws of exponents and radicals

Subtopic

Laws of exponents and radicals under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Simplify the expression p2p9\frac{p^2}{p^9}.

    A.

    p7p^7

    B.

    p−7p^{-7}

    C.

    p11p^{11}

    D.

    1p−7\frac{1}{p^{-7}}

  2. 2.

    Simplify the expression (5x3)2(5x^3)^2.

    A.

    10x610x^6

    B.

    25x625x^6

    C.

    25x525x^5

    D.

    10x510x^5

  3. 3.

    Evaluate the expression 144/169\sqrt{144/169}.

    A.

    12/1312/13

    B.

    14/1614/16

    C.

    12/16912/169

    D.

    144/13144/13

Download the worksheet for Number - Laws of exponents and radicals to practice offline. It includes additional chapter-level practice questions.

Scientific notation (Standard Form)

Subtopic

Scientific notation (Standard Form) under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Write 0.03×10−20.03 \times 10^{-2} in standard form.

    A.

    3×10−43 \times 10^{-4}

    B.

    3×10−33 \times 10^{-3}

    C.

    3×10−53 \times 10^{-5}

    D.

    0.3×10−30.3 \times 10^{-3}

  2. 2.

    Express 400×10−5400 \times 10^{-5} in standard form.

    A.

    4×10−74 \times 10^{-7}

    B.

    4×10−34 \times 10^{-3}

    C.

    0.4×10−20.4 \times 10^{-2}

    D.

    4×10−44 \times 10^{-4}

  3. 3.

    Convert 0.5×1040.5 \times 10^4 to standard form.

    A.

    5×1035 \times 10^3

    B.

    5×1045 \times 10^4

    C.

    5×1055 \times 10^5

    D.

    0.5×1040.5 \times 10^4

Download the worksheet for Number - Scientific notation (Standard Form) to practice offline. It includes additional chapter-level practice questions.

Percentages, profit and loss, simple and compound interest

Subtopic

Percentages, profit and loss, simple and compound interest under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If the ratio of boys to girls in a class is 1:41:4, what percentage of the class are girls?

    A.

    25%25\%

    B.

    20%20\%

    C.

    80%80\%

    D.

    75%75\%

  2. 2.

    An amount of 600600 is invested at 4%4\% simple interest for 66 months. How much interest is earned?

    A.

    2424

    B.

    1212

    C.

    144144

    D.

    66

  3. 3.

    A pair of shoes costs 8080. The price is reduced by 20%20\% and then increased by 20%20\%. What is the final price?

    A.

    8080

    B.

    76.8076.80

    C.

    8484

    D.

    6464

Download the worksheet for Number - Percentages, profit and loss, simple and compound interest to practice offline. It includes additional chapter-level practice questions.

Ratio, proportion, and rates of change

Subtopic

Ratio, proportion, and rates of change under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If 1212 items cost $4.80\$4.80, what is the cost of 55 items?

    A.

    $1.80\$1.80

    B.

    $2.00\$2.00

    C.

    $2.40\$2.40

    D.

    $2.50\$2.50

  2. 2.

    Express the ratio of 1010 minutes to 22 hours in its simplest form.

    A.

    5:15:1

    B.

    1:121:12

    C.

    1:201:20

    D.

    1:61:6

  3. 3.

    Solve for xx in the following proportion: x5=1210\frac{x}{5} = \frac{12}{10}.

    A.

    44

    B.

    55

    C.

    66

    D.

    2424

Download the worksheet for Number - Ratio, proportion, and rates of change to practice offline. It includes additional chapter-level practice questions.

Absolute values

Subtopic

Absolute values under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If x=−2x = -2, find the value of ∣3x∣|3x|.

    A.

    -6

    B.

    6

    C.

    5

    D.

    -5

  2. 2.

    Evaluate ∣−0.1∣|-0.1|.

    A.

    0.1

    B.

    -0.1

    C.

    0

    D.

    1

  3. 3.

    Find the value of ∣−6∣−∣−4∣|-6| - |-4|.

    A.

    2

    B.

    -2

    C.

    10

    D.

    -10

Download the worksheet for Number - Absolute values to practice offline. It includes additional chapter-level practice questions.

Compound and double inequalities

Subtopic

Compound and double inequalities under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Solve the inequality: −3≤x+4≤3-3 \le x + 4 \le 3.

    A.

    −7≤x≤−1-7 \le x \le -1

    B.

    1≤x≤71 \le x \le 7

    C.

    −7<x<−1-7 < x < -1

    D.

    −3≤x≤3-3 \le x \le 3

  2. 2.

    What is the solution to 1<2x−5<71 < 2x - 5 < 7?

    A.

    3<x<63 < x < 6

    B.

    6<x<126 < x < 12

    C.

    3≤x≤63 \le x \le 6

    D.

    4<x<74 < x < 7

  3. 3.

    Solve: x+6<4x + 6 < 4 or x+6>8x + 6 > 8.

    A.

    x<−2x < -2 or x>2x > 2

    B.

    x<10x < 10 or x>14x > 14

    C.

    −2<x<2-2 < x < 2

    D.

    x=−2,2x = -2, 2

Download the worksheet for Number - Compound and double inequalities to practice offline. It includes additional chapter-level practice questions.

Surds, roots and radicals, including simplifying

Subtopic

Surds, roots and radicals, including simplifying under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    What is the value of 0\sqrt{0}?

    A.

    11

    B.

    Undefined

    C.

    00

    D.

    −1-1

  2. 2.

    What is the value of 1\sqrt{1}?

    A.

    0.50.5

    B.

    11

    C.

    00

    D.

    22

  3. 3.

    Simplify the expression 8+18\sqrt{8} + \sqrt{18}.

    A.

    26\sqrt{26}

    B.

    626\sqrt{2}

    C.

    525\sqrt{2}

    D.

    10210\sqrt{2}

Download the worksheet for Number - Surds, roots and radicals, including simplifying to practice offline. It includes additional chapter-level practice questions.

Number systems notation

Subtopic

Number systems notation under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Is the number 25\sqrt{25} rational or irrational?

    A.

    Rational

    B.

    Irrational

    C.

    Neither

    D.

    Imaginary

  2. 2.

    In scientific notation a×10ka \times 10^k, what is the restriction on aa?

    A.

    0<a<100 < a < 10

    B.

    1≤a<101 \le a < 10

    C.

    1<a≤101 < a \le 10

    D.

    aa can be any number

  3. 3.

    What is the value of −32-3^2?

    A.

    99

    B.

    −9-9

    C.

    −6-6

    D.

    66

Download the worksheet for Number - Number systems notation to practice offline. It includes additional chapter-level practice questions.

Direct and inverse proportion

Subtopic

Direct and inverse proportion under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If y=12xy = \frac{12}{x}, find yy when x=0.5x = 0.5.

    A.

    6

    B.

    12

    C.

    24

    D.

    48

  2. 2.

    If y=25xy = \frac{2}{5}x, find yy when x=15x = 15.

    A.

    6

    B.

    10

    C.

    3

    D.

    12

  3. 3.

    The time TT to fill a pool is inversely proportional to the number of hoses nn. If 2 hoses take 10 hours, how many hoses are needed to fill it in 4 hours?

    A.

    4

    B.

    5

    C.

    8

    D.

    10

Download the worksheet for Number - Direct and inverse proportion to practice offline. It includes additional chapter-level practice questions.

Number sequences (prediction, description)

Subtopic

Number sequences (prediction, description) under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Predict the next term in the sequence 10,100,1000,10000,…10, 100, 1000, 10000, \dots.

    A.

    11000

    B.

    20000

    C.

    100000

    D.

    100001

  2. 2.

    What is the common difference in the sequence 2.5,3.5,4.5,5.5,…2.5, 3.5, 4.5, 5.5, \dots?

    A.

    0.5

    B.

    1

    C.

    1.5

    D.

    2

  3. 3.

    What is the next term in the sequence −1,−3,−5,−7,…-1, -3, -5, -7, \dots?

    A.

    -8

    B.

    -9

    C.

    -10

    D.

    -11

Download the worksheet for Number - Number sequences (prediction, description) to practice offline. It includes additional chapter-level practice questions.

Laws of exponents with fractional and rational exponents-extended

Subtopic

Laws of exponents with fractional and rational exponents-extended under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Evaluate the expression: 642364^{\frac{2}{3}}

    A.

    16

    B.

    8

    C.

    32

    D.

    4

  2. 2.

    Evaluate the expression: 4−14^{-1}

    A.

    −4-4

    B.

    0.25

    C.

    0.4

    D.

    −1-1

  3. 3.

    Simplify the expression: x45×x15x^{\frac{4}{5}} \times x^{\frac{1}{5}}

    A.

    x425x^{\frac{4}{25}}

    B.

    x1x^1

    C.

    x5x^5

    D.

    x35x^{\frac{3}{5}}

Download the worksheet for Number - Laws of exponents with fractional and rational exponents-extended to practice offline. It includes additional chapter-level practice questions.

Logarithms, including laws of logarithms-extended

Subtopic

Logarithms, including laws of logarithms-extended under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Express log⁡xy2\log_x y^2 using the power rule.

    A.

    (log⁡xy)2(\log_x y)^2

    B.

    2log⁡xy2 \log_x y

    C.

    log⁡x(2y)\log_x (2y)

    D.

    12log⁡xy\frac{1}{2} \log_x y

  2. 2.

    Evaluate log⁡2(2×4)\log_2 (2 \times 4).

    A.

    8

    B.

    3

    C.

    2

    D.

    6

  3. 3.

    Solve for xx: log⁡10x=−2\log_{10} x = -2.

    A.

    -20

    B.

    0.01

    C.

    0.02

    D.

    -100

Download the worksheet for Number - Logarithms, including laws of logarithms-extended to practice offline. It includes additional chapter-level practice questions.

Upper and lower bounds-extended

Subtopic

Upper and lower bounds-extended under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    A number n=4.7n = 4.7 is rounded to 11 decimal place. What is the error interval?

    A.

    4.65≤n<4.754.65 \le n < 4.75

    B.

    4.6≤n<4.84.6 \le n < 4.8

    C.

    4.65<n≤4.754.65 < n \le 4.75

    D.

    4.7≤n<4.84.7 \le n < 4.8

  2. 2.

    A speed is 6060 km/h correct to 11 significant figure. What is the lower bound?

    A.

    5555 km/h

    B.

    5050 km/h

    C.

    5959 km/h

    D.

    4545 km/h

  3. 3.

    The length of a book is 2020 cm correct to the nearest 22 cm. What is the upper bound?

    A.

    2121 cm

    B.

    2222 cm

    C.

    20.520.5 cm

    D.

    21.521.5 cm

Download the worksheet for Number - Upper and lower bounds-extended to practice offline. It includes additional chapter-level practice questions.

Exponential equations without logarithms

Subtopic

Exponential equations without logarithms under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Solve for xx: 32x−1=273^{2x-1} = 27.

    A.

    x=1x = 1

    B.

    x=2x = 2

    C.

    x=3x = 3

    D.

    x=1.5x = 1.5

  2. 2.

    Solve for xx: 16x=416^x = 4.

    A.

    x=0.5x = 0.5

    B.

    x=2x = 2

    C.

    x=4x = 4

    D.

    x=0.25x = 0.25

  3. 3.

    Solve for xx: 10x−1=10010^{x-1} = 100.

    A.

    x=1x = 1

    B.

    x=2x = 2

    C.

    x=4x = 4

    D.

    x=3x = 3

Download the worksheet for Number - Exponential equations without logarithms to practice offline. It includes additional chapter-level practice questions.

Time zones, clocks, and timetables

Subtopic

Time zones, clocks, and timetables under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    A satellite orbits Earth every 9090 minutes. How many orbits does it complete in 1212 hours?

    A.

    66 orbits

    B.

    88 orbits

    C.

    1010 orbits

    D.

    1212 orbits

  2. 2.

    Express 22 hours 1515 minutes in hours as a decimal.

    A.

    2.152.15 hours

    B.

    2.252.25 hours

    C.

    2.302.30 hours

    D.

    2.502.50 hours

  3. 3.

    If a flight departs at 23:5523:55 and the duration is 1010 minutes, what is the arrival time?

    A.

    00:0500:05

    B.

    23:6523:65

    C.

    00:1500:15

    D.

    24:0524:05

Download the worksheet for Number - Time zones, clocks, and timetables to practice offline. It includes additional chapter-level practice questions.

Constant of proportionality and graphs of direct and inverse proportion-extended

Subtopic

Constant of proportionality and graphs of direct and inverse proportion-extended under Number for Grade 9 IB.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If yy is directly proportional to xx, which statement is true about the graph?

    A.

    It is a curve.

    B.

    It passes through (0,0)(0, 0).

    C.

    It is a vertical line.

    D.

    It has a negative yy-intercept.

  2. 2.

    The number of days DD to paint a house is inversely proportional to the number of painters nn. If D=12D = 12 when n=1n = 1, how many days will it take if n=3n = 3?

    A.

    36

    B.

    4

    C.

    9

    D.

    15

  3. 3.

    If y=kx2y = kx^2 and the graph passes through (2,20)(2, 20), find kk.

    A.

    10

    B.

    5

    C.

    40

    D.

    4

Download the worksheet for Number - Constant of proportionality and graphs of direct and inverse proportion-extended to practice offline. It includes additional chapter-level practice questions.