Add and subtract fractions (2) What common denominator can ... · Add and subtract fractions (2) 1...
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Add and subtract fractions (2) 1 Amir is using fraction strips to work out 2 3 + 1 4 Amir says he needs to find a common denominator. a) Complete Amir’s method. 2 3 = 12 1 4 = 12 2 3 + 1 4 = 12 + 12 = 12 b) Show the addition on the fraction strip. c) Could you have used a different denominator? 2 What common denominator can you use to add the fractions? a) 2 5 + 1 2 Common denominator = b) 2 3 + 4 5 Common denominator = c) 7 8 – 1 4 Common denominator = d) 7 9 – 1 6 Common denominator = e) 11 15 + 3 10 Common denominator = 3 Ron and Eva are working out 1 4 + 5 6 Ron’s method Eva’s method a) What is the same about Ron’s and Eva’s methods? b) What is different about their methods? c) Which method do you prefer? Why? © White Rose Maths 2019 1 4 + 5 6 = 3 12 + 10 12 = 13 12 1 4 + 5 6 = 6 24 + 20 24 = 26 24
Transcript of Add and subtract fractions (2) What common denominator can ... · Add and subtract fractions (2) 1...
Add and subtract fractions (2)
1 Amirisusingfractionstripstoworkout 23
+ 14
Amirsaysheneedstofindacommondenominator.
a) CompleteAmir’smethod.
23
=12
14
=12
23
+ 14=
12 + 12 = 12
b) Showtheadditiononthefractionstrip.
c) Couldyouhaveusedadifferentdenominator?
2 Whatcommondenominatorcanyouusetoaddthefractions?
a) 25
+ 12
Commondenominator=
b) 23
+ 45
Commondenominator=
c) 78
– 14
Commondenominator=
d) 79
– 16
Commondenominator=
e) 1115
+ 310
Commondenominator=
3 RonandEvaareworkingout 14
+ 56
Ron’s method Eva’s method
a) WhatisthesameaboutRon’sandEva’smethods?
b) Whatisdifferentabouttheirmethods?
c) Whichmethoddoyouprefer?Why?
©WhiteRoseMaths2019
14 + 5
6 = 312 + 10
12 = 1312
14 + 5
6 = 624 + 20
24 = 2624
4 Completethecalculations.
a) 15
+ 34
= c) 12
– 17
=
b) 78
– 13
= d) 1118
+ 712
=
5 Moisdrawingjumpsonanumberline.
Thejumpsarethesamesize.
a) Whatisthesizeofthejump?
b) WhatisthevalueofA?
6 Completethebarmodel.
518
16
59
©WhiteRoseMaths2019
7 Completetheadditions.
Giveyouranswersasmixednumbersandasimproperfractions.
a) 45
+ 54
= = c) 98
+ 89
= =
b) 23
+ 32
= = d) = = 53
+ 35
Whatpatternsdoyounotice?
8 Lookattheseadditions.
a) Whendoesthispatternfirstgiveananswergreaterthan2?
b) Doyouthinkthepatternwillevergiveananswergreater
than100?
15
13
A12
+ 13
= 12
+ 13
+ 14
= 12
+ 13
+ 14
+ 15
=
