Week 07 · Equal and compare fractions
Wednesday
Compare fractions
// Same amount, different parts
⏱ about 15 min
Wednesday: Compare fractions
Riley and Bennie each fill a jar with blueberries from the same bush.
"My jar is 2/3 full," says Riley. "Yours is 3/4 full."
"Which jar has more?" he asks. "The thirds and fourths do not match!"
Bennie thinks for a moment. "Then let us make them match."
"Thirds and fourths can both become twelfths."
"2/3 is 8/12, and 3/4 is 9/12. Now we can compare."
Riley laughs. "Nine twelfths is more. Your jar wins this puzzle!"
Learn it: make a common denominator
2/3 = (2 × 4)/(3 × 4) = 8/12.
3/4 = (3 × 3)/(4 × 3) = 9/12.
8/12 is less than 9/12, so 2/3 < 3/4.
MAKE A COMMON DENOMINATOR
- Read the question.
- Tap your answer.
2/3 = ?/12
3/4 = ?/12
1/2 = ?/6
2/5 = ?/10
Learn it: a common numerator
3/5 and 3/8 have the same numerator.
Fifths are bigger parts than eighths.
Three big parts are more than three small parts, so 3/5 > 3/8.
COMPARE THE FRACTIONS
- Read the question.
- Tap your answer.
2/3 ? 3/43/5 ? 3/85/6 ? 2/3
4/10 ? 40/100
COMPARE AGAIN
- Read the question.
- Tap your answer.
7/12 ? 2/3
2/8 ? 2/5
5/8 ? 3/4
9/10 ? 89/100
ORDER THE FRACTIONS
- Think of each as twelfths.
- Put them from least to greatest.
11st
22nd
33rd
44th
Make a common denominator or a common numerator.
| Sentence | True or false? |
|---|---|
| 2/3 < 3/4 | ? |
| 3/5 > 3/8 | ? |
| 5/8 > 3/4 | ? |
| 4/10 = 40/100 | ? |
| We can only compare fractions of the same whole. | ? |
WHY THIS EXERCISE5/8 is less than 3/4, because 3/4 is 6/8.
Try it
Fill two same-sized cups with water. Make one 2/3 full and one 3/4 full.
Line them up side by side.
Which cup has more water? Does it match 8/12 and 9/12?
Line them up side by side.
Which cup has more water? Does it match 8/12 and 9/12?
Draw two bars the same length that compare 2/5 and 1/2.
Sharp comparing! Tomorrow Chris tells a trail story with fractions.