Three of the following four numbers are alike in a certain way and one is different. Choose the number that does not belong to the group.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 980
Compare the middle digit of each number with the sum of its first and last digits.
Option (1) 980 — \( 9 + 0 = 9 \), but the middle digit is 8.
Option (2) 495 — \( 4 + 5 = 9 \), and the middle digit is 9.
Option (3) 341 — \( 3 + 1 = 4 \), and the middle digit is 4.
Option (4) 297 — \( 2 + 7 = 9 \), and the middle digit is 9.
In 495, 341 and 297 the middle digit is the sum of the outer digits; 980 breaks this, so 980 is the odd one out.