Math / Grade 4
Subtract equal fraction parts
Learning goal: Keep the whole and piece size fixed, subtract the selected count, and check the remainder by addition.
Before you start: Name equal parts of a fixed whole, subtract whole-number counts and recognize equivalent fractions.
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Subtract Equal Fraction Parts - Practice 1
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Video transcript and practice. Reading or printing does not count as playback time or an assessed grade.
1. Some ribbon leaves
Video: 0:00
Our pretend ribbon shop has seven ninths of a strip. A customer takes two ninths. How much stays? Every ninth must be one of nine equal parts of the same whole strip. The picture has seven loaded parts and two empty spaces. Those spaces were never part of the order. We are subtracting ribbon, not shrinking our ruler.
2. Subtract the count, not the size
Video: 0:27
Cross out two of the seven ninth-size pieces. Five pieces stay. Seven minus two is five, so seven ninths minus two ninths is five ninths. The bottom number stays nine because each piece is still one ninth of our whole. Subtracting nine from nine would give a zero denominator, which does not define a fraction.
3. Put the order back together
Video: 0:52
Check the subtraction by putting the pretend pieces back. Five ninths stayed, and two ninths left. Five ninths plus two ninths makes seven ninths, our starting amount. This addition check catches a missing piece. It is like checking the shop receipt, except nobody needs a wallet and the ribbon cannot escape under the counter.
4. Keep the extra whole
Video: 1:17
Now the shop starts with thirteen tenths. Ten tenths fill one whole strip, and three tenths sit in a second matching strip. Two tenths leave. Thirteen minus two is eleven, so eleven tenths stay. That is one whole and one tenth. Subtraction can leave more than one whole. Do not throw away the full strip just because another strip is only partly filled.
5. Pause: a different order
Video: 1:45
Try a new order. Start with nine tenths and remove four tenths of the same whole. Pause the video. How many tenths stay? Say or write the fraction, then add the removed four tenths back to check it. You may draw equal parts or explain aloud. Keep the bottom number connected to the size of each piece.
6. Check the five remaining parts
Video: 2:10
Nine minus four is five, so five tenths stay. Five tenths is also one half because five of the ten equal parts fill half the strip. Our check is five tenths plus four tenths equals nine tenths. If you wrote five tenths or one half, both name the same remaining amount. A different name does not mean different ribbon.
7. An empty order is still an answer
Video: 2:35
What if all the ribbon leaves? Four sixths minus four sixths leaves zero sixths, which is zero. We still used sixth-size pieces; we did not divide by zero. Fun fact: the addition check works even here. Zero plus four sixths rebuilds four sixths. An empty load is a valid result, not a broken fraction or a failed delivery.
8. Continue to the worksheet
Video: 3:02
Continue to the worksheet below. It has new amounts, so use the method rather than copying a video answer. Keep the whole and piece size fixed, subtract the counts, and check by adding back what left. Keep extra wholes and allow zero when everything leaves. Then try the second sheet or choose Unloading in Fraction Dock for more guided practice.
Show your understanding
You can point, explain aloud, draw or write.
- Subtract numerators with a shared positive denominator and explain why the piece size stays unchanged.
- Check a remainder by adding back the removed amount, including zero and amounts above one whole.
Try it yourself
Pause at nine tenths minus four tenths. Find the remaining fraction and check it by adding back the removed part.
Continue to the worksheet with fresh amounts, then try Practice 2 or choose Unloading at Fraction Dock.
Next: your worksheet
Subtract Equal Fraction Parts - Practice 1https://s3u.com/mf4e1
Try Fraction Dock: choose Unloading
Lesson: https://s3u.com/lessons/subtract-equal-parts