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CommonMultiplesandtheLCM
Video218onwww.corbettmaths.com
Workout
Question1: (a)Writedownthe@irsttenmultiplesof2.
(b)Writedownthe@irsttenmultiplesof3.
(c)Listthe@irstthreecommonmultiplesof2and3.
Question2: (a)Writedownthe@irsttenmultiplesof4.
(b)Writedownthe@irsttenmultiplesof5.
(c)Listthe@irstthreecommonmultiplesof4and5.
Question3: Writedownthreecommonmultiplesofeachofthesepairsofnumbers.
(a)2and5 (b)3and4 (c)4and6 (d)10and15
(e)20and30
(f)3and5 (g)6and9 (h)6and12
Question4: (a)Writedownthe@irsttenmultiplesof5.
(b)Writedownthe@irsttenmultiplesof8.
(c)Findthelowestcommonmultiple(LCM)of5and8.
Question5: (a)Writedownthe@irsttenmultiplesof6.
(b)Writedownthe@irsttenmultiplesof8.
(c)Findthelowestcommonmultiple(LCM)of6and8.
Question6: Findthelowestcommonmultiple(LCM)ofeachofthesepairsofnumbers.
(a)5and6 (b)2and7 (c)3and8 (d)4and10
(e)9and4 (f)6and7 (g)6and8 (h)9and12
(i)15and40
(j)12and20
(k)13and4 (l)18and6
(m)25and35
(n)22and33
(o)16and24
(p)20and28
Question7: Findthelowestcommonmultiple(LCM)ofeachofthesesetsofnumbers.
(a)2,3and5
(b)3,4and5
(c)2,5and7
(e)10,12and15
(f)2,3,4and5
(g)1,2,3,4,5and6.
© CORBETTMATHS 2016
(d)5,6and9
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CommonMultiplesandtheLCM
Video218onwww.corbettmaths.com
Apply
Question1:
Atoadcroaksevery8seconds.
Afrogcroaksevery6seconds.
Theybothcroakatthesametime.
Afterhowmanysecondswilltheynextbothcroakatthesametime?
Question2: AbusleavesAntrimBusStationevery12minutes.
AtrainleavesAntrimTrainStationevery18minutes.
At8amabusandatrainleavethestationsatthesametime.
(a)Whenisthenexttimethatabusandatrainleaveatthesametime?
(b)Between8amand11am,onhowmanyoccasionsdoesabusandatrain
leaveatthesametime?
Question3: Thelowestcommonmultipleoftwonumbersis60.
Onlyoneofthenumbersisamultipleof4.
Writedowntwopossiblenumbers.
Question4: Thelowestcommonmultipleoftwonumbersis70.
Bothnumbersarelessthan20.
Writedowntwopossiblenumbers.
Question5:
Aredlight@lashesevery6seconds.
Agreenlight@lashesevery15seconds.
Abluelight@lashesevery21seconds.
Theyhaveall@lashedatthesametime.
Afterhowmanysecondswilltheynextall@lashatthesametime?
Question6: ExplainwhyCharlieiswrong
Question7:
PennyandKennyhavethesamenumberoffootballcards.
Pennyhassortedhercardsintopilesof10.
Kennyhassortedhiscardsintopilesof18.
Pennyhaslessthan100cards.
Howmanyfootballcardsdotheyhave?
Question8: Jennifersaysthatthelowestcommonmultipleoftwoconsecutivenumbers
isequaltotheproductofthetwonumbers.
Bytryingfourdifferentpairsofconsecutivenumbers,explorehertheory.
© CORBETTMATHS 2016