How_To_Be_Good_At_Math

CALCULATING • PARTITIONING FOR DIVISION 139

Imagine you’re going on holiday in 291 days

and you want to know how many weeks you

have to wait until the holiday begins. You know

there are 7 days in a week, so you need to divide

291 by 7 to find out the number of weeks.

Since we know from the multiplication

table for 7 that 7 × 4 = 28, we also know

that 7 × 40 = 280, which is very close to, but not

more than, the dividend (291). Let’s partition 291

into 280 and 11.

As we know that 7 × 40 = 280, we also

know that 280 ÷ 7 = 40

Now we divide 11 by 7. The answer

is 1 remainder 4.

Adding up our quotients and

including the remainder gives

the final answer 41 r4.

So, 291 ÷ 7 = 41 r4

Remember, we’re counting in

weeks, so we can also write the

answer as 41 weeks and 4 days.

Divide the two
parts separately

291 ÷ 7 = 41 r4

291 ÷ 7 =?

291

280

280 ÷ 7 = 40

11

11 ÷ 7 = 1 r4

40 + 1 r4 = 41 r4

Including remainders

Sometimes, dividing by partitioning leaves us with

remainders. But the method we’ve just seen still works

• we simply have to include the remainders when we
  add up our answers (or quotients) at the end.

138_139_Partitioning_for_division.indd 139 29/02/2016 18:03