Question

Find the product of the :

(i) greatest number of three digits and smallest number of five digits.

(ii) greatest number of four digits and the greatest number of three digits.

Answer 1

(i) Greatest number of three digits = 999

and Smallest number of five digits = 10000

Required product = 999 x 10000 = 9990000

(ii) Greatest number of four digits = 9999

and Greatest number of three digits = 999

Required product = 9999 x 999

= 9999 x (1000 – 1)

= 9999 x 1000 – 9999 x 1 (using distributivity)

= (10000- 1) x 1000 – (10000- 1) x 1

= 10000 x 1000 – 1 x 1000 – 10000 + 1

= 10000000 – 1000 – 10000 + 1

= 10000001 – 11000

= 9989001