Order the rational numbers from least to greatest

0.42, - 1/2, 11/20, - 0.51

Negative comes before positive ...

-5 - 4 - 3 - 2 - 1 0 1 2 3 4 5

Put it in order using a number line.

This is simple. Simple math. Just know that negative is below zero. If there is a negative number, it's always lower than a positive number. - 1/2 is -.50. If you look at it like money. 11/20 is 0.55. The rest is self-explanatory. So, the order least to greatest would be - 0.51, - 1/2, 0.42, 11/20. - 0.51 < - 1/2 < 0.42 < 11/20