Quick: Review Multiplying Decimals by 0,100,1000,10000 V 4 \0( [OQ i [000, [0 000 0M > I Use mental math to multiply a decimal by 10,100,100ft and 10 000. > Wherfrydu multiply a decimal by 10, /2.45X 10=* 245 the dlgijl shift 1 place to the left / 0,432X10=* 4.32 You show this by moving the decimal point 1 place to the right. \ 6.8 X 10 = 68 > When you multiply a decimal by 100, /1.367 X 100= 136.7 the digits shift 2 places to the left You show this By moving the decimal point 2 places to the right ( \ 5.3 X 100 = 530 0.25 X10a=*25 > When you multiply a decimal b 100ft / 5.846 X 1000 = 5846 the digits shift 3 places to theleftf / 3.21 X 1000 3210 Yotl show this by moving the decimal point 3 places to the right \ 0.004 X 1000 = 4 > When you multiply a decimal by 10 000 f / 0.245 X 10 000 = 2450 the digits shift 4 places to the left ( 1.26 X 10000= 12600 You show this by moving the decimal \ 0.8 X 10 000 = 8000 point 4 places to the right : Try These j Use mental math to find each product Ik? la) ic^<4kr 1. a) 6.5 X 10 = Qtf b) 734 X 10 = *J3 M c) 0.461 X 10 = 6.5 X 100 = (Q^O 734 X 100 = l^h 0.461 X 100 = ^JoJ 6.5 X 1000 = C^OO 734 X 1000 = 0.461 X 1000 = 4^ / 6.5 X 10000 = <cbo0d 734 X 10000 = 7-^ g 0.461 X 10000 = 4^/o 2. a) 1.9 X 10 = / \ b) 6.73 X 100 = &73 c) 9.365 X 10 000 = JHj o 48 d) 2.6 X 100 = Mo e) 7.2 X 1000 = 1X00 f) 0.486 X 1000 = ^/2> > g) 2.63 X 10 = h) 1.123 X 100 = lti>^ i) 0.586 X 10 000 = $ o
Practice Use mental math. fa) Jp^eM^ 1. Use the information in the table to find the mass of each set of coins. a) 10 000 quarters l f^ooo^b) 100 nickels 39i c) 1000 dimes / 7^D(^ e) 100 toonies If 3 O a g) 10 nickels d) 10 pennies 23 «S J f) 1000 nickels??5b <j 3 9< 5^ e?. h) 10 000 dimes / 7^0 0 Q, Masses of Coins Coin Mass (g) Penny 2.35 Nickel 3.95 Dime 1.75 Quarter 4.4 Toonie 7.3 2. Multiply. a) 5.03 b) 6.714 c) 0.415 d) 62.3 X 10 X 100 X 1000 X 10 000 6> i3 OOD e) 62.345 X 1000 f) 8.173 X 10 000 m no g) 0.542 X 100 S» 2. h) 3.7 X 1000 31 DO 3. Write each distance in metres. a) 6.59 km fp b90/m b) 0.927 km mc) 37.459 km? 7 V d) 3.8 km i &^C7 M e) 5.47 km C^0_m f) 6.28 km 3 *n 4. One bottle of spicy sauce has a capacity of 0.725 L. What is the capacity of 10 bottles? 1'2^L 1000 bottles? L 10000 bottles? 7^S^oL 5. The width of a quarter is 23.88 mm. What is the distance covered by each number of quarters laid side by side? a) 10 3 9. 9 M/M b) ioo 3369 m^i c) IOOOO 23 d %QD ^Stretch Your Thinking 1. Use the table in Practice question 1 to find the mass of: a) 101 pennies 7*?^ b) 1001 nickels 3?S"3.qs^ 19so f- ^ 5 c) 11 quarters?8.7y ^ ^ d) 110dimes I 9-?-^ 49
Mu Itiplying Who[e IP% ] Numbers by O.T r 0.01,0.001 0*1/ 0*01 } 0.001 ate <C QU2GI( Review Use mental math to multiply a whole number by 0.1,0.01, and 0.001 T > When you multiply by OA, the digits shift 1 place to thgrighfc, /f\ulfstp To show this, move the decimal point 1 place to theleft. 27 X 0.1 = 2.7 > When you multiply by 0.01, the digits shift 2 places to the right. To show this, move the decimal point 2 places to the left. 27 X 0.01 = 0.27 > When you multiply by CL001, the digits shift 3 placesto the right. To show this, move the decimal point 3 placesjojhejeft. 27 X 0.001 = 0.027 O a TffTfiese ) Use mental math to multiply; 1. a) 2 X 0.1 =* 0*7 b) 74 X 0,1 = _ 2 X 0.01 = 0-0 7 74 X 0.01 = 2 X 0.001 = P, ODl 74 X 0.001 = 0.07Y d) 5 X 0.1 = 0<f e) 60 X 0.1 =. 6.0 f) 5 X 0.01 = O'O^ 60 X 0.01 = 5 X 0.001 = CP. OPf 60 X 0.001 2. a) 13 X 0.1 = ^ J b) 52 X 0.001 d) 59 X 0.01 = O-g'f e) 3 X 0.01 = g) 519 X 0.001 = O&Cf h) 152 X 0.1 = j) 7 X 0.1 = 0, 7 k) 6 X 0.001 = - 0.06 = 0. Oi'Z cl ML f) /f.j i) 235X0.1 = 235 X 0.01 235 X 0.00T 164X0.1 = 164X0.01 164 X 0.001 8 X 0.01 =. 231 X 0.001 6 X 0.001 = 73 X 0.01 = = 0,2^o.og = Q.13J Q-73 sa
Practice Use mental math to multiply. 1. a) 20 X 0.01 = 0,10 b) 63 X 0.001 = M13 c) 9 X 0.1-0. f d) 7 X 0.001 = 0*007 e) 3 X 0.01 = 0-0h f) 568 X 0.01 = ± 3 g) 354 X 0.1 = 33^7 h) 28 X 0.1 - Q* 8 i) 158 X 0.001 = QJfB 2. Complete the table. Number x 0.1 x 0.01 x 0.001 39 3 9" 0,039 H7 4.7 0.H7 ira 1 S r J 1.52 je 0.098 194 0*19*1 a) 75 b) 1 c) 71 d) 13 X 0.1 X 0.001 X 0.01 X 0.1 7*f o.ool 0.7V e) 9 f) 154 g) 62 h) 486 X 0.01 X 0.01 X 0.001 X 0.1 0 to 6 2~* 4. One jellybean has a mass of 0.001 kg. What is the mass of 98 jellybeans? O-Do/x 9B - 0<Q?g /r f/t mass o?& *J^6e&t. Stretch Your Thinking A flower seed has a mass of 0.1 g. - What is the mass of 200 of these seeds? O* /x - 30*$J 17 #fctxt, How many seeds would it take to make 0.5 kg? itq.qo f t^dj ( kct ~ /boo f 53
UNIT 4 Drvidfntt Decimals by 10,100,1000,10000 '..., Quick Review r Use mental math to divide a decimal by 10,100,1000, and TO OOO. When you divide a decimal by 10, t 3.62* 10=0.362 the digits shift 1 place to the right 8.7* 10 = 0.87 You show this by moving the decimal 6.8 * TO = 0.68 point % place to the teft; When you divide a decimal by 100, 1.63* 100=0.0163 the digits shift 2 places to the right. 5.6* 100 = 0.056 You show this by moving the decimal 3* 100 = 0.03 point 2 places to the left. When you divide a decimal by 1000, 4.415 * 1000 = 0.004 15 the digits shift 3 places to the right 7.2 * 1000=0.0072 You show this by moving the decimal 1 * 1000 = 0.001 point 3 places to the left. When you divide a decimal by 10 000, 7.5* 10000=0.00075 the digits shift 4 places to the right. 1.4* 10000=0.00014 You show this by moving the decimal 6* 10 000 = 0.0006 point 4 places to the left. it. rrytfiesa Use mental math to find each quotient 1. a) 8.2 * 10 = b) 5 * 10= 0»*>' 8.2 * 100= 0*0 5 * 100= 0*0^ 8.2 * 1000 = O.OObl 5 * 1000= 0*0Of 8.2 * 10000 = O-OOPBl 5 * 10000 = 0, OOOf 2. a) 3.4 * 10 = O'lH b) 1.63* 100 = &#f 3 c) 1.12 * 1000 = 0*60 f/3 d\ 05*100= 0. 00fe) 8* 10000 = ^^1 fj 7* 10000 = 0-00O7 g) 5.17 * 10 = 0* fl h) 9.6 * 1000^0_ D0lh 0 6382 * 10 = 0*1,1% 2 SO L
Practice Use mental math. 1. a) 0.23 -MO = 0*0 ^3 b) 6 * 10 000 = Q. 0OO(> c) 78.3 1000= 0,0 76 3 d) $8.90* 10 = ^o.8y e) 0.47 * 1000 = 0. OOP H 7 f) 2.146 * 100 = 0.0X7# 2. Write the missing divisor in each division sentence, a) 4.23 * 70Q = 0.0423 b) 0.738 * (O = 0.0738 c) 5 * /OQ = 0.05 d) 3.2 * /o OOP = 0.000 32 e) 0.12 * /OOP = 0.000 12 f) 173 + /p OOP = 0.0173 3. A pile of 10 000 sheets of paper is 85 cm thick. What is the thickness of 1 sheet of paper? 0- OQQfo^i ~ 6S~-r (o ODD 4. One hundred 50C coins have a mass of 690 g. What is the mass of one 50C coin? (eo^cj. ~& ^0 r loo 5. Jacob's scarf is 79 cm long. Write this length in as many different units as you can. 11-.(oo*o- 7? rvt 7f x<0'= 7?c?M/h lo-- 79 ct*.^nm^,, 6. Sandy drank 575 ml of water during her walk. Cl^ ~ ^OOj^L^ Write this amount in litres. 7<T'-f (000 - Q, ^JbT L /T)7. Keshav jogged 1257 m today. (k*a- /&C?0 fa (m ~/oo cwi /W - / Write this distance in the units indicated. I ~ ( C o JJs<7W000 -f'ls'fkm: cm; 12 S7o dm; J i L ^ m m ^T)8. Helena's hair is 6.4 dm long. Write this length in metres. & - c f -r /D ^ Q.j)H m 9. One thousand seeds have a mass of 200 g. What is the mass of 1 seed? 'loo-fooq- 0*3 J ^ m a / { /^\ Stretch Your Thinking ^"~L)ne quarter has a mass of 4.4 g. A bag of quarters has a mass of 2.64 kg. What is the total value of the quarters? _