Question

Which one is least to greatest? explain how you know. ( - = negative)

Answer 1

You have a choice here - either convert the fractions to decimals if you have a calculator or just know the values, or convert the decimals to fractions and find the common denominator. Here I will do both to illustrate it.

Let's get all the numbers mentioned here, -2/3, -1/5, 0.4, and 2.

Firstly, decimals:
-2/3 = -0.666...
-1/5 = -0.2

Secondly, and slightly more complicated, fractions:
0.4 = 4/10
2 = 20/10 (for the sake of using the same denominator)

Now we need to find a common denominator for all of the fractions
The lowest common multiple of 3 5 and 10 is 30, so lets put them all over 30:
-1/5 = -6/30
-2/3 = -20/30
4/10 = 12/30
2 = 60/30

Now we can see the numbers more clearly, which shows us the the correct answer is D