How many three-digit natural numbers are divisible by 9?

1.	How many three-digit natural numbers are divisible by 9?
Answer» 3-digit numbers: 100, 101,…….,999 3-digit numbers divisible by 9 : 108, 117, 126, 135, …, 999 Here, a = 108, d= 9, l = 999 a_n (l) = a + (n – 1) d 999 = 108 + (n – 1) x 9 (n – 1) x 9 = 999 – 108 = 891 n – 1 = 99 n = 100

Answer»

3-digit numbers: 100, 101,…….,999

3-digit numbers divisible by 9 : 108, 117, 126, 135, …, 999

Here, a = 108, d= 9, l = 999

a_n (l) = a + (n – 1) d

999 = 108 + (n – 1) x 9

(n – 1) x 9 = 999 – 108 = 891

n – 1 = 99

n = 100

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