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Doubles and Halves. Lets learn all about it. Select a number from below and double it. 57. 16. 65. 24. 34. 93. 43. How did you get your answer ?. This slide will show you multiples of 10 between 10 and 1000. What will be in the units column when a number is a multiple of 10?
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Doubles and Halves Lets learn all about it
Select a number from below and double it 57 16 65 24 34 93 43 How did you get your answer ?
This slide will show you multiples of 10 between 10 and 1000 • What will be in the units column when a number is a multiple of 10? • Yes you are correct all multiples of 10 have a o in the units place. • Examples are • 90 130 220 340 520 630 and on and on and on. The units column will have a zero.
What is Double H T U 3 4 0 • How do you know the answer to this? • First check to see is the number a multiple of 10. • To work it out you double the hundreds digit first, then double then tens digit and add them together. • Lets partition the number 300+40 • Double 300=600 Double 40=80 add them together and you get 680 as your answer to
Double HTU 260 Lets double the hundreds and then double the tens and add them together. • 200+200=400 • 60+60=120 • Added altogether 400+120=520
Lets half a number What is Half 1,420? Is this a multiple of 10? Lets apply the same method as before only in reverse. T H T U 142 0 Half the thousands = 500 Half the hundreds = 200 Half the tens = 10 Then add them altogether to get half = 710 The half of 1,420 is 710
Lets get you to work ! • To double a number you must……. • Double the hundreds, the tens and then the units and add them all up. • To half the number you must • half all the hundreds, the tens and the units and add them up. Remember: All multiples of 10 are easy! No need to worry about that units column.
