Which number have the least absolute value - 5, - 10, - 20, - 30

-5

Absolute value means the difference away from one. So, it doesn't matter if it's negative or not. As long as the number is closer to one so the smaller number always has the least absolute value. The absolute values of the numbers give in least to greatest order is |5|,|10|,|20|, and |30|. You put lines outside to represent it's the absolute value.