Q11 of 119 Page 45

Evaluate:
(i) 88 × 92 (ii) 78 × 82.

(i) We have

88 × 92 = (90 – 2) × (90 + 2)

= (90² – 2²)

= 8100 – 4

= 8096

(ii) We have

78 × 82 = (80 – 2) × (80 + 2)

= (80² – 2²)

= 6400 – 4

= 6396

Using the formula (a - b)² = (a² - 2ab + b²), evaluate:

(i) (196)² (ii) (689)² (iii) (891)²

Evaluate:

(i) 69 × 71 (ii) 94 × 106.

Fill in the blanks:

(i) The square of an even number is….

(ii) The square of an odd number is…….

(iii) The square of a proper fraction is ………..than the given fraction.

(iv) n² = the sum of first n ……. natural numbers.

Write (T) for true and (F) for false for each of the statements given below:

(i) The number of digits in a perfect square is even.

(ii) The square of a prime number is prime.

(iii) The sum of two perfect squares is a perfect square.

(iv) The difference of two perfect squares is a perfect square.

(v) The product of two perfect squares is a perfect square.

Evaluate:(i) 88 × 92 (ii) 78 × 82.