Question

how many 3 digits numbers between 100 and 550

Answer 1

Answer:

449

Step-by-step explanation:

We can solve this in many ways

I will show you my favourite methods

1st method (logical method)

we know,

3 digit numbers between are 101, 102, 103,........,549

so, when we subtract the 1st and the last number we get

Number of 3 digit numbers after 101

549 - 101 = 448

So there are 448 3-digit numbers after 101 but we didn't add 101

so, 448 + 1 = 449

So, the general formula will be

(l - a) + 1

where l represents the last term, a represents the first term

2nd method (Arithemetic Progression)

3 digit Numbers between 100 and 550 are

101, 102, 103,.......,549

So, the first term a = 101, and the common difference d = 1

we know that,

a(nth) = a + (n - 1)d

l = 549 where l stands for last term

549 = 101 + (n - 1)(1)

n - 1 = 549 - 101 = 448

n = 448 + 1 = 449

Thus, there are 449 3-digit numbers between 100 and 550

Hope you understood it........All the best