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Mathematics Magazine for Grades 1-12  

 

11-2004
 

 

  

Grade 3

Theory: 

Multiplying by 100s

  • How to multiply by hundreds:

  • Move the decimal point two places to the left.

  • For example: 8 × 400 would become 8 × 4

  • Do the multiplication (8 × 4 = 32)

  • Move the decimal point of the product two places to the right (=3200)

Solutions from the Previous Issue:

Calculate:

1.        (16 – 8) × (27 ÷ 3 ) =

Solution:

(16 – 8) × (27 ÷ 3 ) = 8 × 9 = 72

2.        (51 – 9) ÷ (12 – 5) =

Solution:

(51 – 9) ÷ (12 – 5) = 42 ÷ 7 = 6

3.        (54 – 9) × (72 ÷ 9) =

Solution:

(54 – 9) × (72 ÷ 9) = 45 × 8 = 360

4.        (63 ÷ 9) × (86 – 78) =

Solution:

(63 ÷ 9) × (86 – 78) = (63 ÷ 9) × (86 – 78) =

 7 × 8 = 56

Proposed Exercises:

Complete the following table

n

21

19

39

69

64

57

n × 12

 

 

 

 

 

 

n × 12 + 8

 

 

 

 

 

 

 

 
 
 

Read more on the written version of the publication