Question

a number with 2 consecutive natural digits, how many units will it increase if written in reverse order. Detail solution pls

Answer 1

It will increase by 9 units.

Explanation:

We can write the lowest number as 10a + (a + 1) and the highest is the reverse which is 10(a + 1) + a.

Subtracting:

10(a + 1) + a - (10a + a +1)

= 10a + 10 + a - 10a - a - 1

= 10a - 10a + a - a + 10 - 1

= 10 - 1

= 9.