2 Writethenumbersinthesortingdiagram.

1234568121524

Completethesentence.

Thecommonfactorsof15and24are

3 Findthecommonfactorsofeachpairofnumbers.

a) 12and20

b) 16and25

c) 20and50

d) 20and60

Common factors

1 a) Use18countersorcubes.

Makeasmanydifferentarraysaspossible,usingallthe

cubesorcounters.

Useyourarraystohelpyoulistthefactorsof18

Thefactorsof18are

b) Use24countersorcubes.

Makeasmanydifferentarraysaspossible,usingallthe

cubesorcounters.

Useyourarraystohelpyoulistthefactorsof24

Thefactorsof24are

c) Whatarethecommonfactorsof18and24?

©WhiteRoseMaths2019

factorsof15 factorsof24

4 a) Completethetable.

Factorpairsof50 Factorpairsof75 Factorpairsof100

1 × 50

2 × 25

5 × 10

1 ×

b) Whatarethecommonfactorsof50,75and100?

5 List3commonfactorsof360and180thataregreaterthan50

6 Alexismakingpartybags.

Shehas35sweetsand25balloons.

Thesweetsandballoonsneedtobesharedequally,sothateach

baghasthesamenumberofsweetsandballoons.

IsAlexcorrect?

Explainyouranswer.

©WhiteRoseMaths2019

7

WhatnumberisAnniethinkingof?

8 Whitneyistryingtosimplifythesefractions.

ShowhowWhitney’smethodcouldwork.

Talkaboutyouranswerwithapartner.

I can put 5 sweets and 5 balloons in each bag

because 5 is a common factor of 35 and 25

My number has a factor of 7 in common

with Annie’s number.

The common factors of my number and Annie’s number

are 1, 5 and 10

I am thinking of a 2-digit number.

I can use common factors to work out how to

simplify these fractions.

18

46

24

81

121

132

40

100

Ron

Annie

Dexter