Lesson 4 of 19
Taking one fraction from another
Show on a big screenYou have 3/4 of a ribbon roll. You cut away 1/6 for a border. How much is left?
Step 1 of 4
- A strip cut into twelfths.
- 3/4 renamed is 9/12.
- Take away 1/6, renamed as 2/12.
- Left over: 9/12 − 2/12 = 7/12.
Rename, then take away
7/12 of the roll is left.
Rename both fractions onto one shared bottom number. Subtract the top numbers. Keep that bottom number.
Steps of 4 and steps of 6 both reach 12. 12 is 3 steps of 4, so 3/4 is 9/12. 12 is 2 steps of 6, so 1/6 is 2/12. Then 9 − 2 = 7. The roll has 7/12 left.
Sometimes there is not enough to take away. You cannot take 1/2 from 1/3. 1/2 is more than 1/3.
Slide to cross out pieces in the lab. Stop when the crossed-out part matches the fraction taken away.
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Try the lab to finish this lesson.