Christina B. answered • 08/27/19
Experienced, Positive, and Effective Tutor with an M.Ed.
Hi Jaclyn,
It is difficult to compare fractions with different numerators. You need to do something to put them into like terms to help you see which one is larger. There are at least a few strategies I can think of that might help you to compare these fractions:
- Draw a model. It does not need to be circular, You could use rectangles of the same size. You would, however, have to be careful to accurately divide one into eighths and one into fifths.
- Convert the fractions into equivalent fractions with a common denominator.
- Convert the fractions into decimals which can be compared.
You are probably working with equivalent fractions, so I will model how to do that.
We need to find a multiple that 5 and 8 have in common. Let's list them out:
5: 5, 10, 15, 20, 25, 30, 35, 40, 45
8: 8, 16, 24, 32, 40, 48
It looks like 40 is the least common multiple that both denominators have in common. So we're going to convert 3/8 and 2/5 to 40ths.
In order to find an equivalent fraction, we need to multiply the numerator and the denominator by the same value.
3/8 = 3•5/8•5 = ?/40
2/5 = 2•8/5•8 = ?/40
If you complete the multiplication, you will find which fraction has the greater value and who ate more pizza.
________________
An alternative method of solving this problem is to convert fractions to decimals. We can think of every fraction as a division problem. For example, 2/5 can become 2÷5. If you complete the math, either by using long division or a calculator, you will find that 2/5 = 0.4. You can do the same for 3/8. When you compare the decimals, you will see that one is slightly greater than the other.
If this answer was helpful, please click the thumbs-up.
