krit.club logo

Number - Exponents and Square Roots

Grade 6IB

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

🔑Concepts

Exponents represent repeated multiplication of the same number. In the expression ana^n, aa is the 'base' and nn is the 'exponent' or 'index'. For example, 252^5 means multiplying 22 by itself 55 times: 2×2×2×2×2=322 \times 2 \times 2 \times 2 \times 2 = 32. Visually, imagine a growth pattern where a value doubles at every step.

Squaring a number involves raising it to the power of 22 (x2x^2). Visually, this can be represented as a geometric square where the side length is xx and the total number of units inside is the result. For example, 323^2 forms a 3×33 \times 3 grid of dots, totaling 99 dots.

A Square Root (x\sqrt{x}) is the inverse operation of squaring. It asks: 'What number multiplied by itself gives this value?' If you visualize a square with an area of 2525 square units, the square root is the length of one side, which is 55 units. The symbol \sqrt{} is known as the radical sign.

Perfect Squares are integers that result from squaring another whole number. Common perfect squares include 1,4,9,16,25,36,49,64,81,1, 4, 9, 16, 25, 36, 49, 64, 81, and 100100. On a number line, these are specific landmarks where the distance from zero corresponds to the area of a square with integer sides.

Powers of 1010 follow a unique pattern where the exponent tells you exactly how many zeros follow the digit 11. For instance, 102=10010^2 = 100 (two zeros) and 106=1,000,00010^6 = 1,000,000 (six zeros). This is a foundational concept for understanding place value and scientific notation.

In the Order of Operations (BODMAS/PEMDAS), exponents and roots are calculated right after Brackets and before Multiplication, Division, Addition, or Subtraction. For example, in the expression 5+235 + 2^3, you must evaluate 23=82^3 = 8 first, then add 55 to get 1313.

📐Formulae

an=a×a×a(n times)a^n = a \times a \times a \dots (n \text{ times})

x2=x×xx^2 = x \times x

If x2=y, then y=x\text{If } x^2 = y, \text{ then } \sqrt{y} = x

10n=100...0 (where there are n zeros)10^n = 100...0 \text{ (where there are } n \text{ zeros)}

💡Examples

Problem 1:

Evaluate the expression: 23+812^3 + \sqrt{81}

Solution:

Step 1: Calculate the value of the exponent: 23=2×2×2=82^3 = 2 \times 2 \times 2 = 8. \ Step 2: Calculate the value of the square root: 81=9\sqrt{81} = 9 (because 9×9=819 \times 9 = 81). \ Step 3: Add the two results together: 8+9=178 + 9 = 17.

Explanation:

Apply the order of operations by solving exponents and roots first, then performing the addition.

Problem 2:

A square floor is covered by 144144 identical square tiles. How many tiles are along one edge of the floor?

Solution:

Step 1: Recognize that the total number of tiles represents the area of the large square: Area=144Area = 144. \ Step 2: To find the number of tiles along one edge (the side length), take the square root of the total: 144\sqrt{144}. \ Step 3: Determine which number multiplied by itself equals 144144. Since 12×12=14412 \times 12 = 144, then 144=12\sqrt{144} = 12.

Explanation:

This uses the geometric interpretation of square roots, where the square root of an area gives the side length of a square.