Division Strategies Revision

• Halving and Halving Strategy  

E.g. 96 ÷ 24 = 4

48 ÷ 12 = 4

24 ÷ 6   = 4

12 ÷ 3   = 4

• Using Known Facts Strategy 

This strategy, as the name suggests, involves breaking up the problem into know pieces  to make it easier.

E.g. 136 ÷ 8 = ?

10 x 8 = 80 (136 - 80 = 56)

56 ÷ 8 = 7

There are 10 groups of 8 in the 80, and 7 groups of 8 in 56, so altogether there are 17 groups of 8 in 136, => 136 ÷ 8 = 17.

Multiplication Practise

Think about what would be the best strategy then have a go at practising with the following problems.

5 x 84 =        

9 x 17 =

8 x 45 =

78 x 5 =

97 x 4 =

3 x 14 =

4 x 33 =

5.8 x 8 =

9 x 12.4 =

4.2 x 4 =

8.9 x 4 =

Get someone at home to write you some new problems so you can keep practising.
Also check out Room 11's blog. They have videos of kids explaining how to use all the strategies.

Multiplication Strategies Revision

Multiplication

• Place Value Strategy

(Good for problems that have multiple digit numbers that end in 1, 2, 3, 4, 5)

Eg. 6 x 15 = (6 x 10) + (6 x 5)

= 60 + 30

= 90

• Rounding and Compensating Strategy

(Good for problems that have multiple digit numbers that end in 6, 7, 8, 9)

Eg. 7 x 19 = (7 x 20) - (7 x 1)

= 140 - 7

= 133

• Doubling and Halving Strategy (Can also be applied as Tripling and Thirding)

E.g 5 x 46 = 10 x 23  (Double the ‘5’, and halve the ’46’)

= 230 

Or. 3 x 24 = 9 x 8     (Triple the ‘3’ and third the ’24’)

Subtraction Practise

45 - 17 =

3.1 - 1.9 =

345 - 231 =

68 - 52 =

12.7 - 3.3 =

93 - 34 =

When you have finished, ask someone at home to write you some more similar problems.

Subtraction Strategy Practise

• Place Value Strategy

Eg. 47 - 34 = 47 - 30 - 4

      = 17 - 4

      = 13

Or. 82 - 19 = 82 - 10 - 9

      = 72 - 9 (The nine is split into parts to make this step easier)

      = 72 - 2 - 7

      = 70 - 7

      = 63

• Equal Adjustment Strategy

(The second number in the equation is rounded up or down to a ‘tidy ten’, an equal amount must then be added or subtracted from the first number. NB In subtraction problems, you either add to both numbers OR subtract from both numbers)

Eg. 123 - 49 = 124 - 50

+1     +1 

       = 74

E.g. 84 - 52 = 82 - 50

-2   -2 

     = 32

- Reversibility Strategy 

(A subtraction equation can be reversed and made into an addition problem. A number line can then be used to help solve the problem)

Eg. 73 - 29 = ?

29 + ? = 73

29 30     70       73

    +1    +40      +3

29 + 44 = 73

so 73 - 29 = 44

Addition Strategy Practise

Have a go at these. Remember the same rules apply when you solve decimal problems, you just have to  make sure you are using the right place value columns.
You can choose which strategy you would like to use, but use all of the different strategies at some stage.

1)    34 + 78 =

2)    359 + 102 =

3)    3.8 + 6.9 =

4)    57 + 88 =

5)    23.7 + 12.4 =

If you have finished these, ask someone at home to write some similar problems for you to solve.
Ask if you get stuck!

Addition Strategy Revision

Today we revised the 3 key addition strategies. They are:

• Place Value Strategy

(Numbers are separated into the tens and ones)

Eg.    45 + 13 = (40 + 10) + (5 + 3)

                        = 50 + 8

                        = 58

- Advanced Place Value Strategy - Holding the biggest number

Or. 57 + 47 = 57 + 40 + 7

                   = 97 + 7

                   = 104

• Rounding and Compensating Strategy

(One of the numbers is rounded up or down to a ‘tidy ten’, an equal amount must then be taken away or added to the other number in the equation to balance it. NB: In addition problems you use two different actions addition/subtraction)

Eg. 63 + 59 = 62 + 60

-1     +1  

                    = 122