Answer 1

Numbers between 100 and 1000 are 3-digit numbers.

A 3-digit number is to be formed from the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 where unit place digit is 4.

Since Unit’s place digit is 4.

∴ it can be selected in 1 way only.

10’s place digit can be selected in 10 ways. For 3-digit number 100’s place digit should be a non-zero number.

∴ 100’s place digit can be selected in 9 ways.

∴ By using fundamental principle of multiplication, total numbers between 100 and 1000 which have 4 in the units place

= 1 × 10 × 9

= 90