Here, every 3 digit number would need 3 presses and every 4 digit number would need 4 presses ⇒ 3 digit numbers from 121 to 999 = 999 – 121 +1 = 879 ⇒ 4 digit numbers from 1000 to 1346 = 1346 – 1000 + 1 = 347 So, total number of presses = (879) × 3 + 347 × 4 = 2637 + 1388 ⇒ 4025 ∴ the correct option is 4)