Download
multiplication by multiples of 10 and 100 n.
Skip this Video
Loading SlideShow in 5 Seconds..
Multiplication by multiples of 10 and 100 PowerPoint Presentation
Download Presentation
Multiplication by multiples of 10 and 100

Multiplication by multiples of 10 and 100

1168 Vues Download Presentation
Télécharger la présentation

Multiplication by multiples of 10 and 100

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Multiplication by multiples of 10 and 100 Objective to multiply numbers when 0’s are involved

  2. Starter • What is the rule for multiplying a whole number by 10? • Write down the number and add a zero • What is the rule for multiplying a whole number by 100? • Write down the number and add two zeros

  3. 47 X 10 23 X 100 16 X 100 52 X 10 84 X 10 79 X 100 31 X 100 95 X 1000 58 X 10,000 470 2,300 1,600 520 840 7,900 3,100 95,000 580,000 Calculate the following:

  4. Main Activity • Calculate 30 X 40 • Multiply 3 X 4 • 12 • How many zeros in the question? • Two • 30 X 40 = 1200 • OR 3 X 4 = 12 30 X 4 = 120 so 30 X 40 =1200

  5. Another example • Calculate 40 X 500 • Multiply 4 by 5 • 20 • How many zeros in the question? • Three • 40 X 500 = 20,000

  6. Yet another example • Calculate 700 X 300 • Multiply 7 by 3 • 21 • How many zeros in the question? • Four • 700 X 300 = 210,000

  7. 200 X 70 60 X 30 800 X 400 2,000 X 30 14,000 1,800 320,000 60,000 Lets check that we understand

  8. The rule-plenary • We are to multiply two numbers that are multiples of powers of ten • Firstly we multiply the two digits together ignoring the zeros • We work out how many zeros in the question • We add the number of zeros to our initial answer