How_To_Be_Good_At_Math

130 CALCULATING •^ DIVIDING WITH MULTIPLES

Dividing with multiples

We’ve already used number lines to add, subract, and multiply. We can also use

them to see how many times one number (the divisor) fits into another (the dividend).

The division is easier if you jump forward in multiples of the divisor.

+

10 × 3 = 30 4 × 3 = 12

10 groups of 3

What about remainders?

Sometimes our jumps don’t quite reach the target. In cases

such as this, we’re left with a remainder. Let’s see what

happens when we use a number line to divide 44 by 3.

0 5 10 15 20 25 30 35 40 44

4 groups of 3

We can’t add another

group of 3 without

going past our target,

so our remainder is 2

Let’s calculate 27 ÷ 3. We’ll

start at 0 and make jumps

of 2 groups of 3 each time.

Each jump moves us 6 places.

Four jumps gets us to 24.

A last jump of 3 takes us to

27. We’ve jumped 9 groups of 3
    in total, so that’s the answer.

If we made bigger jumps,

we could get to the answer

with fewer steps.

27 ÷ 3 =?

44 ÷ 3 =?

27 ÷ 3 = 9

44 ÷ 3 = 14 r2

2 × 3 = 6 2 × 3 = 6 2 × 3 = 6 2 × 3 = 6 1 × 3 = 3

(^0612182427)
2 groups
of 3
2 groups
of 3
2 groups
of 3
2 groups
of 3

• 
  
  
  
  • 
    
    
    
    • 
      
      
      
      • 1 group
        of 3
        = 9 groups
        of 3
        = 14 groups
        of 3
        30
        Add up
        all the 3s
        A first big jump of 10 groups of 3
        moves us 30 places. Then a jump of
        4 groups of 3 moves us on another 12.
        Our two jumps have taken us
        to 42, but we’re 2 places short
        of 44. So our remainder is 2.
        42
        The bigger the
        multiples, the fewer
        steps you need.
        130-131_Dividing_with_Multiples.indd 130 29/02/2016 14:11