Slide 2:
Multiplying whole numbers by
10’s, 100’s, 1000’s etc 1 x 10 = 10 5 x 10 = 50 12 x 10 = 120 135 x 10 = 1350 What do you notice about each new answer? Quick method : add a zero to the end of the whole number when multiplying by 10 Multiplying a whole number by 10 A zero is added to the end of the number
Slide 3:
What would you do if you multiplied by 100? 1 x 100 = 100 5 x 100 = 500 12 x 100 = 1200 135 x 100 = 13500 Quick method : add a zero to the end of the whole
number for each multiply of 10 x 10 add 1 zero x 100 add 2 zero x 1000 add 3 zero etc
Slide 4:
Multiplying decimals by 10’s 1.5 x 10 = 15 1.23 x 10 = 12 3 Each zero represents one movement of the decimal place to the right. . . 0.5 x 10 = 5 13.23 x 10 = 132 3 . . If decimal point lands at the end you do not have to write it in Remember, if decimal point lands at the end you do not have to write it in
Slide 5:
Multiplying decimals by 100’s 1.56 x 100 = 156 51.234 x 100 = 5123 4 Each zero represents one movement of the decimal place to the right, thus 2 movements to the right . . 0.5 x 100 = 13.23 x 100 = 1323 . . If decimal point lands at the end you do not have to write it in Remember, if decimal point lands at the end you do not have to write it in Don’t forget to add an extra zero 50
Slide 6:
Dividing decimals by 10’s 1.5 10 = 12.3 10 = Each zero represents one movement of the decimal place
to the left . 0.5 10 = 1323 10 = . If decimal point lands at the beginning add a zero in front If decimal point lands at the beginning add a zero in front 0 15 1.23 05 0 . Remember, there is a decimal point at the end of the number 132 3
Slide 7:
Dividing decimals by 100’s 1.5 100 = 12.3 100 = Each zero represents one movement of the decimal place
to the left . 321.5 100 = 1323 100 = . If decimal point lands at the beginning add a zero in front 0 15 123 3 215 . Remember, there is a decimal point at the end of the number 13 23 0 . 0