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

Smallest number of five digits = 10000

Required product = 999 × 10000

= 9990000

(ii) Greatest number of four digits = 9999

Greatest number of three digits = 999

Required product = 9999 × 999

= 9999 × (1000 – 1)

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

= (10000 – 1) × 1000 – (10000 – 1) × 1

= 10000000 – 1000 – 10000 + 1

= 10000001 – 11000

= 9989001