TheLondon2012OlympicsStadium
Roundingandestimating
Toestimateornot,thatisthe
question.
©EdWebster2012
https://www.flickr.com/photos/ed_webster/7916292438
Thestadiumcouldseat84,000peopleforthe2012Olympics
andwillseat54,000asthehomeofWestHamFootballClub
in2016.
© www.teachitmaths.co.uk 2014
23077
1
© www.teachitmaths.co.uk 2014
FootballStadium
©EricSoler2011
https://www.flickr.com/photos/spam64/6749996529
OldTraffordfootballstadiumisthehometoManchesterUnitedFootballClub.
Howmanypeopledoyouthinkitcanseat?
23077
3
OldTraffordfootballstadiumcanseat75,731people.
Whatisthisfigureroundedtothenearestthousand?
© www.teachitmaths.co.uk 2014
FootballStadium
4
©RossHuggett 2012
https://www.flickr.com/photos/rosshuggett/7866132282
OldTraffordholds75,731seats.
Whenwouldyouuseanestimate?
Canyouthinkofwhenanexactfiguremightbeused?
23077
23077
Recordtimes
©EricSoler2011
https://www.flickr.com/photos/spam64/6749996529
© www.teachitmaths.co.uk 2014
2
FootballStadium
©EricSoler2011
https://www.flickr.com/photos/spam64/6749996529
© www.teachitmaths.co.uk 2014
23077
UsainBoltwonthe100 metresgoldmedalatthe2012LondonOlympicswith
atimeof9.63seconds.ThiswasanewOlympicrecord.
Whatisthistimeroundedtothenearestsecond?Wasthistimeestimated?
5
© www.teachitmaths.co.uk 2014
23077
6
1
Time
Travellingtimesanddistances
© kezee 2011
https://www.flickr.com/photos/kezee/5928257777
IrecentlydrovefromBathtoGlasgow.
Itisadistanceof618kmor384miles.Iaveraged100km/hor61.5mph.
HowcouldIroundthesefigurestoreportthemasestimates?
Whatistheexacttimeontheclock?
Whatwouldyoutellafriendwhoaskedyouwhatthetimewas?
© www.teachitmaths.co.uk 2014
23077
7
© www.teachitmaths.co.uk 2014
23077
8
Prices
Astronomicaldistances
ImageprovidedcourtesyofNASA
http://spaceplace.nasa.gov/planetweather/en/8_planets.jpg
©ThePizzaReview(PizzaPieer)2008
https://www.flickr.com/photos/thepizzareview/2322274380
TheEarthorbitsthesun.Atitsclosest,itis147,098,074km
awayandatitsfurthest,152,097,701kmaway.
Whydoyouthinkanadvertforaconvertiblecarusedthetag
line‘93millionmilesofheadroom’?
© www.teachitmaths.co.uk 2014
23077
Thispizzacosts£8.75tobuy.Whywouldyounotroundthisupto£10?
Howwouldyouestimatethecostoffivepizzasatthisprice
9
© www.teachitmaths.co.uk 2014
23077
Houseprices
Houseprices
© Sludge G 2010
https://www.flickr.com/photos/sludgeulper/4809446789
© Sludge G 2010
https://www.flickr.com/photos/sludgeulper/4809446789
Thesehouseswerevaluedat£197,750eachrecently.
Ifyouweretalkingtoafriendaboutthecostofeachhouse,
whatwouldyouprobablysayeachonecost?
Thesehouseswerevaluedat£197,750eachrecently.
Whatpricewouldyouuseifyouwerebuyingthehouse?
© www.teachitmaths.co.uk 2014
23077
11
© www.teachitmaths.co.uk 2014
23077
10
12
2
Theroundingrule
Estimatingandrounding
Theruleforroundingis…
• 5oroverroundup
• Under5rounddown
Youhavenow
consideredrounding
andestimating.
Quickten,tothenearestwholenumber– True/False?
Whatrulemightyou
suggestforrounding
andestimating?
1.
2.
3.
4.
5.
© Michael Coghlan (Familiar Sight) 2012
https://www.flickr.com/photos/mikecogh/7822806770
2.5roundsto3
1.1roundsto1.1
2.5roundsto2
9.9roundsto10
2.19roundsto3
6.
7.
8.
9.
10.
8.888roundsto8
27.0roundsto30
5.5roundsto5
0.6roundsto1
6.45roundsto7
Whycould6.46roundtoeither6.5orto10?
© www.teachitmaths.co.uk 2014
•
•
•
•
•
23077
© www.teachitmaths.co.uk 2014
23077
14
Roundtonearest10
Roundtonearest100
Answers
Answers
•
•
•
•
•
27
122347
632
4096
8585
© www.teachitmaths.co.uk 2014
•
•
•
•
•
•
13
•
•
•
•
•
•
30
122350
630
4100
8590
23077
15
•
•
•
•
•
•
270
122347
632
4096
8585
6982
© www.teachitmaths.co.uk 2014
300
122300
600
4100
8600
7000
23077
16
Roundtonearest1000
Roundtonearest10th
Answers
Answers
•
•
•
•
•
•
2700
122347
632
4096
8585
6982
© www.teachitmaths.co.uk 2014
23077
•
•
•
•
•
•
3000
122000
1000
4000
9000
7000
17
•
•
•
•
•
•
2.71
122.347
63.209
40.96
85.85
6.982
© www.teachitmaths.co.uk 2014
23077
2.7
122.3
63.2
41.0
85.9
7.0
18
3
Roundtonearest100th
Answers
•
•
•
•
•
•
•
•
•
•
•
•
0.271
122.347
63.209
40.999
85.8509
6.982
© www.teachitmaths.co.uk 2014
23077
0.27
122.35
63.21
41
85.85
6.98
19
4