Transcript Multiples
Warm up – back of your books 1. Three businessmen sell a Car for £2451. They decide to divide the money evenly between themselves. How much do each get? 2. Mr Dad has seven sons. Each is to receive an equal share of his land, totalling 8022 acres. How many acres does each son get to keep? • Three businessmen sell a Car for £2451. They decide to divide the money evenly between themselves. How much do each get? Use the ‘bus shelter’ method... 0 8 1 3 2 2 4 5 7 2 1 Each would get £817... • Mr Dad has seven sons. Each is to receive an equal share of his land, totalling 8022 acres. How many acres does each son get to keep? 1 7 1 1 4 6 3 4 8 0 2 2 Each would get 1146 acres... Multiples We will be discovering how to identify if a BIG number is a multiple of a SMALL number You will be able to identify multiples of 2,3,4,5 and 6 Tests of Divisibility • Which of these numbers divide by 2? How do you know? 18 2341 9 123 568.4 266 32 190 Numbers that are divisible by 2 end in a 0, 2, 4, 6 or 8 (ie) They are even!) Tests of Divisibility • Which of these numbers divide by 3? How do you know? 30 3+0=3 321 3+2+1=6 6 6=6 3003 3+0+0+3=6 61 6+1=7 17 1+7=8 165 1 + 6 + 5 = 12 224 2+2+4=8 Numbers that are divisible by 3 have digits that add up to a multiple of 3... Tests of Divisibility • Which of these numbers divide by 4? How do you know? 16 16 ÷ 4 = 4 224 24 ÷ 4 = 6 312 12 ÷ 4 = 3 732 32 ÷ 4 = 8 509 09 cannot divide by 4 5604 04 ÷ 4 = 1 918 18 cannot divide by 4 342 42 cannot divide by 4 Numbers are divisible by 4 if their last 2 digits are divisible by 4... Tests of Divisibility • Which of these numbers divide by 5? How do you know? 23 540 2735 732 730 71 295 502 Numbers are divisible by 5 if their last digit is either 0 or 5... Tests of Divisibility • Which of these numbers divide by 6? How do you know? 12 1+2=3 540 5+4+0=9 123 152 1+5+2=8 1+2+3=6 But not Even 732 7 + 3 + 2 = 12 258 2 + 5 + 8 = 15 9246 9+2+4+6 51 5+1=6 But not Even Numbers are divisible by 6 if they are divisible by both 2 and 3... So they must be even, and their digits add up to a multiple of 3... Plenary • A number is divisible by 6 if it is divisible by both 2 and 3 • Why does this work? • Because 2 x 3 = 6 (ie 2 and 3 are the factors of 6) • If a number is divisible by 3 and 5, what bigger number will it also divide by? • 15 as 3 x 5 = 15 • If another number is divisible by 3 and 7, what will it also divide evenly by? • 21 as 3 x 7 = 21 Summary • We have learnt how check whether certain numbers are divisible by 2, 3, 4, 5, or 6 • As said, this can be useful for checking answers • The patterns can also be used to work out factors of bigger numbers...