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Working with Fractions

Track quiz

Fourteen ideas, fourteen checks. The table goes first, so there is somewhere to look back at.

Fourteen moves for fractions, from the first rename to the last fraction of what is left
MoveHow it goes
Name an amount past one wholeCount every piece for the top-heavy name. Count filled wholes first for the mixed one.
Swap between the two namesWhole times the bottom, plus the top. Or share the top into bottoms.
Find a shared bottom numberCount up in steps of each bottom number until both lists meet.
Add unlike fractionsRename both onto the shared bottom number. Add the tops. Keep the bottom.
Subtract unlike fractionsRename the same way, then take the tops. Never subtract the bottoms.
Combine mixed numbersFlatten both, or carry and borrow between wholes and parts.
Take a fraction of a whole numberDivide by the bottom, multiply by the top.
Multiply two fractionsTops together, bottoms together. No shared bottom needed.
Say which way a product movesTop under bottom shrinks. Top over bottom grows. Equal leaves it.
Divide by a fractionCount how many copies fit, or multiply by the flip.
Cancel firstBefore multiplying, divide a top and a bottom by the same number. The answer stays the same.
Share a fractionMultiply the bottom number by the number of shares. The top stays.
Which way dividing movesDividing by a number between 0 and 1 makes the amount bigger. Dividing by a number above 1 makes it smaller. Dividing by 1 leaves it alone. That holds for any amount above zero.
What is leftFind what is left first. Then take the fraction of that, not of the whole.

You have 7 third-pieces of a paper strip. What is that as a mixed number?

  • 7 1/3
  • 3 1/7
  • 2 1/3

Which bottom number can both 1/2 and 1/5 be renamed onto?

  • 10
  • 7, because 2 + 5 = 7
  • 5, because 5 is the bigger one

What is 1/4 + 1/3?

  • 2/7
  • 7/12
  • 1/12

What is 5/6 − 1/3?

  • 4/3
  • 4/6
  • 3/6, which is 1/2

What is 2 1/3 + 1 5/6?

  • 4 1/6
  • 3 6/9
  • 4 6/9

Two fifths of 20 tiles is how many tiles?

  • 10
  • 8
  • 40

What is 3/5 × 2/3?

  • 5/8
  • 6/8
  • 6/15, which is 2/5

30 is multiplied by each of 4/5, 5/5 and 6/5. Which one comes out bigger than 30?

  • 30 × 6/5
  • 30 × 4/5
  • 30 × 5/5

What is the reciprocal of 7?

  • 7/1, since a whole number already has 1 underneath
  • 1/7
  • 1/1

How many twelfths fit inside 5/6?

  • 1/10
  • 5/72
  • 10

What is 8/15 × 9/10, if you cancel first?

  • 12/25
  • 12
  • 17/25

What is 7/9 ÷ 3?

  • 7/3
  • 3/7
  • 7/27

30 is divided by each of 3/5, 5/5 and 6/5. Which one comes out bigger than 30?

  • 30 ÷ 3/5
  • 30 ÷ 5/5
  • 30 ÷ 6/5

A rope loses 1/3 of its length. Then 1/4 of what is left is cut. What part of the rope remains?

  • 5/12
  • 1/2
  • 1/12

Chapter 8 of Part I is Working with Fractions. You have placed pieces on strips and matched bottom numbers. You have shared a whole into groups. You have seen a multiplier below one shrink an amount.

Next: Geometric Twins. Two figures that match exactly. And the tests that tell you so without measuring everything.

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This track

  1. 0 Start here
  2. 1 More than one whole
  3. 2 Renaming until the pieces match
  4. 3 Adding pieces that do not match
  5. 4 Taking one fraction from another
  6. 5 Wholes and parts together
  7. 6 Checkpoint: renaming, adding and taking away
  8. 7 A fraction of a whole number
  9. 8 A fraction of a fraction
  10. 9 When multiplying makes it smaller
  11. 10 The number that undoes a fraction
  12. 11 How many of these fit inside that
  13. 12 Checkpoint: multiplying and dividing
  14. 13 Cancel before you multiply
  15. 14 Share a fraction equally
  16. 15 When dividing makes it bigger
  17. 16 A fraction of what is left
  18. 17 The big picture
  19. 18 Track quiz

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