Week 08 · Add and subtract fractions
Wednesday
Add mixed numbers
// Join and take away parts of the same whole
⏱ about 15 min
Wednesday: Add mixed numbers
Donnie and Bennie measure the meadow path with a long string.
"On Monday I walked 2 1/4 miles," says Donnie.
"On Tuesday I walked 1 2/4 miles. How far is that in all?"
Bennie draws a number line in the soft dirt.
"Add the wholes, then add the fourths," he says.
"2 and 1 make 3 wholes. 1/4 and 2/4 make 3/4."
"So you walked 3 3/4 miles," Bennie says. Donnie twitches his ears happily.
Learn it: rename mixed numbers
1 3/4 is 1 whole and 3/4. One whole is 4/4.
So 1 3/4 = 4/4 + 3/4 = 7/4.
Going back, 7/4 = 4/4 + 3/4 = 1 3/4.
RENAME THE NUMBER
- Read the question.
- Tap your answer.
1 3/4 = ?/4
2 1/3 = ?/3
11/4 = 2 ?/4
13/10 = 1 ?/10
Learn it: add the wholes, then the parts
2 1/4 + 1 2/4: wholes 2 + 1 = 3, fourths 1/4 + 2/4 = 3/4. Total 3 3/4.
Sometimes the fractions make a new whole.
1 3/4 + 2 2/4: wholes make 3, fourths make 5/4, which is 1 1/4. Total 4 1/4.
ADD MIXED NUMBERS
- Read the question.
- Tap your answer.
2 1/4 + 1 2/4 = ?
3 1/5 + 2 3/5 = ?
1 2/6 + 1 3/6 = ?
4 3/10 + 2 4/10 = ?
MAKE A NEW WHOLE
- Read the question.
- Tap your answer.
1 3/4 + 2 2/4 = ?
2 5/8 + 1 6/8 = ?
3 2/3 + 2/3 = ?
1 1/2 + 1 1/2 = ?
STEPS FOR 1 3/4 + 2 2/4
- Think about how Bennie adds wholes and parts.
- Tap the steps in order.
1First
2Next
3Then
4Last
Add the wholes, then the fractions. Rename if the fraction is a whole or more.
| Sentence | True or false? |
|---|---|
| 1 3/4 = 7/4 | ? |
| 2 1/4 + 1 2/4 = 3 3/4 | ? |
| 1 3/4 + 2 2/4 = 3 5/4 | ? |
| 1 3/4 + 2 2/4 = 3 1/4 | ? |
WHY THIS EXERCISE1 3/4 + 2 2/4 is 4 1/4. The fourths make one more whole.
Try it
Ask a grown-up for a measuring cup with fourths marked on it.
Pour in 1 3/4 cups of water, one fourth cup at a time.
Count the fourth cups you poured. Is it 7?
Pour in 1 3/4 cups of water, one fourth cup at a time.
Count the fourth cups you poured. Is it 7?
Draw a number line from 0 to 3 in fourths. Mark 1 3/4 and 2 1/4.
Wholes and parts, together at last! Tomorrow Chris tells a trail story.