5. Mixed numbers — Learner Route

Fractions · Step 5

Fractions bigger than one

A fraction does not have to be smaller than one. The denominator tells us how many equal pieces make one whole. So if the denominator is 3, then three thirds make one complete whole: 33 = 1. Once we have more than three thirds, we have more than one whole.

Watch thirds build a whole
13
23
33
1 whole
1/3 → 2/3 → 3/3 → 1 whole
Start from the fraction

What does 113 actually mean?

It means eleven pieces, each one third of a whole. To make sense of that amount, group the thirds into complete wholes.

113

Each outlined circle is one whole. Each coloured piece is 1/3. Count the eleven pieces, then watch groups of three build whole circles.

1/31/31/31/31/31/31/31/31/31/31/3Piece 1: one thirdPiece 2: one thirdPiece 3: one thirdPiece 4: one thirdPiece 5: one thirdPiece 6: one thirdPiece 7: one thirdPiece 8: one thirdPiece 9: one thirdPiece 10: one thirdPiece 11: one third3/3 = 1 whole3/3 = 1 whole3/3 = 1 whole2/3 left

11 coloured pieces, each 1/3 of a whole.

Look first

One whole and three quarters

Start with one whole and three quarters. It is one quantity, shown in two parts.

1 whole + 3/4 = 7/4

Split the whole into four quarters, then count those four quarters and the three extra quarters.

1 whole3/4+1/41/41/41/41/41/41/4

One whole circle and three quarters of another circle.

Notice

The amount has not changed

1 whole + 34 = 74
Watch the notation
134 ≠ 134
The whole number and the fraction are separate parts of a mixed number. Do not join the digits together.
Mixed number
It tells us how many complete wholes we have, and then how much of another whole remains.
Improper fraction
It counts every equal-sized piece together, even when there are enough pieces to make one or more whole ones.
Why mixed numbers?

A different way to think about the same quantity

The improper fraction counts all the equal pieces. The mixed number tells us how many complete wholes those pieces make, and what is left over.

113 = 323
These are two equivalent ways to describe exactly the same amount.

Sometimes one form is easier to understand; sometimes the other is easier to calculate with. So we need to be able to move in both directions.

Reverse the process

Mixed number → improper fraction

Now go backwards. First count how many fraction pieces are hidden inside the wholes. Then add the extra pieces.

Keep this one still
2 5 7
2 × 7 → 14 sevenths
2 wholes × 7 sevenths in each whole = 14 sevenths
14 + 5 → 19 sevenths
Then add the 5 extra sevenths.
197
134
1 whole × 4→4 quarters
4 + 3→7 quarters
74
323
3 × 3 = 9→9 thirds
9 + 2 = 11→11 thirds
113
The pattern
1. Multiply the whole number × denominator.
2. Add the numerator.
3. Keep the same denominator.
Interactive lab

What does the picture show?

Count complete wholes and leftover pieces, then choose the matching number.

Choose an answer.
Method Trainer

Move between the two forms

Try fresh examples in either direction, or mix both directions. Results feed into your Practice Lab log on this device. Each question is counted once; after feedback, you can correct your working or move on. Changing direction starts a new set.

How would you like to answer?
1. To convert the whole number into parts, multiply.
×=
2. Add the numerator to the count of parts from step 1.
?+=
3. Keep the denominator
??

You have learned

A mixed number and an improper fraction can describe exactly the same amount.

To move between them, think in equal-sized pieces: build wholes from the pieces, or break wholes back into those pieces.