MathematicsClass 8Squares and Square Roots

Properties of Square Numbers

Identifying patterns and characteristic properties of numbers obtained by squaring integers.

Class 8 · MathematicsCBSE & ICSE SOF IMO

Definition

Properties of square numbers describe the unique mathematical patterns and characteristics that numbers possess when they are multiplied by themselves. These properties include observing the digits at the units place, the sum of consecutive odd numbers, and the difference between squares of consecutive numbers. Recognizing these patterns helps in quickly identifying whether a number can be a perfect square.

Key formula

n^2 - (n - 1)^2 = n + (n - 1)

Worked examples

1

A number ending in 2, 3, 7, or 8 can never be a perfect square, so 107 is not a square number.

2

The sum of the first 4 odd numbers is 1 + 3 + 5 + 7 = 16, which is equal to 4^2.

3

The square of an even number is always even (e.g., 6^2 = 36), and the square of an odd number is always odd (e.g., 5^2 = 25).

Common mistakes

  • Assuming that any number ending in 6 is always a perfect square without checking the tens digit.
  • Believing that numbers ending in 0 can end in an odd number of zeros to be a square.
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