Complete the following activity to find the sum of natural numbers between 1 and 140 which are divisible by 4.

Between 1 and 140, natural numbers divisible by 4: 4, 8, ..., 136 → How many numbers? ∴ \(n = \square\) → \(n = \square, a = \square, d = \square\) → \(t_n = a + (n - 1)d\) → \(136 = \square + (n - 1)\times\square\) → \(n = \square\) → \(S_n = \frac{n}{2}[2a + (n - 1)d]\) → \(S_\square = \frac{\square}{2}[\ \ ] = \square\). Sum of numbers from 1 to 140, which are divisible by 4 = \(\square\)

Doubtly Asked 24 Oct 2026 Save WhatsApp Report

1 answer

Answer: 2380

Numbers: 4, 8, ..., 136, with \(a = 4\), \(d = 4\).

\[136 = 4 + (n - 1) \times 4\]\[n - 1 = 33,\ n = 34\]\[S_{34} = \frac{34}{2}[2(4) + 33(4)]\]\[= 17 \times 140 = 2380\]

So there are 34 such numbers and their sum is 2380.

Doubtly AI · 24 Oct 2026 AI-verified · Oct 2026 Report

Was this answer helpful?

Complete the following activity to find the sum of natural numbers between 1 and 140 which are divisible by 4.

1 answer

Your answer