Round 0.142 to the nearest tenth

The 2 is irrelevant, the 4 determines whether you round up or down. since the four is less than 5 you round down. (if the number to the right is 5 or greater you round up, if it is less than 5 you round down

0.142 = 0.100 = 0.1

If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up (+1).

If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down (no change).

0.142 ≈ 0.1