krit.club logo

Number - Fractions as Division and Fractions of Quantities

Grade 6IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

A fraction ab\frac{a}{b} represents the division of the numerator aa by the denominator bb. This is often written as a÷ba \div b.

•

In the context of sharing, if nn items are shared equally among dd people, each person receives nd\frac{n}{d} of the items.

•

To calculate a fraction of a quantity, divide the total quantity by the denominator (to find the value of one 'part') and then multiply the result by the numerator.

•

The word 'of' in mathematics typically signifies multiplication when dealing with fractions, such as 12\frac{1}{2} of 2020 which is 12×20\frac{1}{2} \times 20.

•

Improper fractions can be converted to mixed numbers using division. For example, 114\frac{11}{4} is 11÷411 \div 4, which equals 22 with a remainder of 33, written as 2342\frac{3}{4}.

📐Formulae

ab=a÷b\frac{a}{b} = a \div b

Fraction of a Quantity=QuantityDenominator×Numerator\text{Fraction of a Quantity} = \frac{\text{Quantity}}{\text{Denominator}} \times \text{Numerator}

ab of Q=(Q÷b)×a\frac{a}{b} \text{ of } Q = (Q \div b) \times a

💡Examples

Problem 1:

Four friends want to share 33 identical pizzas equally. How much pizza does each friend get?

Solution:

3÷4=343 \div 4 = \frac{3}{4}

Explanation:

Since 33 pizzas are being divided among 44 people, the division is 3÷43 \div 4. This is represented as the fraction 34\frac{3}{4}. Each friend receives 34\frac{3}{4} of a pizza.

Problem 2:

Calculate 35\frac{3}{5} of 4545 liters.

Solution:

(45÷5)×3=9×3=27 liters(45 \div 5) \times 3 = 9 \times 3 = 27 \text{ liters}

Explanation:

First, find 15\frac{1}{5} of 4545 by dividing 4545 by 55, which equals 99. Then, multiply by 33 to find the value of three parts.

Problem 3:

Express the improper fraction 173\frac{17}{3} as a mixed number using division.

Solution:

17÷3=5 remainder 217 \div 3 = 5 \text{ remainder } 2, so 173=523\frac{17}{3} = 5\frac{2}{3}

Explanation:

Divide the numerator by the denominator. The quotient (55) becomes the whole number, and the remainder (22) becomes the new numerator over the original denominator (33).

Problem 4:

A bag contains 6060 marbles. 23\frac{2}{3} of them are blue. How many marbles are blue?

Solution:

23×60=(60÷3)×2=20×2=40\frac{2}{3} \times 60 = (60 \div 3) \times 2 = 20 \times 2 = 40

Explanation:

To find 23\frac{2}{3} of 6060, we divide the total number of marbles by 33 to find one part (2020 marbles), and then multiply by 22 to find two parts (4040 marbles).