Adding and Subtracting Fractions

Warm upWhat is the lowest common multiple of:

12

30

12

24

10

3 and 4

5 and 6

4 and 6

3 and 8

5 and 10

Find a the missing numbers

15=

2

5

40=

38

25=5

6

6

15

30

Adding and Subtracting FractionsTwo rulers add three rulers is:

Four pens add five pens is: 9 pens5 rulers

Two pens add Five rulers is:

We can’t so this until we have a name that describes both groups

7 Pieces of equipment

When we add fractions we need them to have the same name

Adding and Subtracting Fractions

27

37

57+ =

29

49

69+ =

111

311

411+ =

Adding and Subtracting Fractions

27

37

57+ =

29

49

69+ =

511

311

211- =

Adding and Subtracting FractionsWe need to make sure the denominator of both fractions is the same

before we add or subtract

25

310

710

+ =

103

10+ =4

We need a number in the 5 and 10 times table to use as our bottom number- 10?

Adding and Subtracting FractionsWe need to make sure the denominator of both fractions is the same

before we add or subtract

13

512

912

+ =

125

12+ =4

We need a number in the 3 and 12 times table to use as our bottom number- 12?

Adding and Subtracting FractionsWe need to make sure the denominator of both fractions is the same

before we add or subtract

25

36

2730

+ =

30 30+ =12

We need a number in the 5 and 6 times table to use as our bottom number- 30?

15

Adding and Subtracting FractionsWe need to make sure the denominator of both fractions is the same

before we add or subtract

78

23

524

- =

24 24- =21

We need a number in the 8 and 3 times table to use as our bottom number- 24?

16

Adding and Subtracting Fractionsa) 7/8b) 8/12c) 7/9d) 7/10e) 2/3

f) 11/12g) 7/10h) 8/15i) 16/12 or 1 ¼j) 11/24

k) 1 7/12l) 1 5/56m) 29/30n) 29/52o) 1 1/10

p) 5/8q) 5/12r) 1/3s) 2/5t) 1/2

u) 7/20 v) 8/21w) 23/36x) 9/22y) 71/126

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