How many numbers between 100 and 1000 have 4 in the unit’s place?

1.	How many numbers between 100 and 1000 have 4 in the unit’s place?
Answer» 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 the unit place digit is 4. 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 a 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 the fundamental principle of multiplication, total numbers between 100 and 1000 which have 4 in the units place = 1 × 10 × 9 = 90.

Answer»

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 the unit place digit is 4.

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 a 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 the fundamental principle of multiplication,

total numbers between 100 and 1000 which have 4 in the units place = 1 × 10 × 9 = 90.

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