Specific Learning Outcomes
Solve problems using a combination of addition, subtraction, multiplication and division mental strategies.
Description of Mathematics
Activity
At this stage, offering students a regular daily dose of mental calculation is strongly recommended. It is a good idea to record only one problem on the board or in the modelling book at a time and not allow the students to use pencil and paper. Make sure they all have time to solve each problem. Don’t allow early finishers to call out the answer.
For example, take the problem 73 – 29 = ?.
Prompt the students to look carefully at the numbers before deciding how they might solve this. The following are possible strategies:
- Equal adjustments: solved by adding 1 to both numbers, so 74 – 30 = 44.
- Rounding and compensating: 73 – 29 becomes 73 – 30 = 43, then 43 + 1 = 44.
- Reversibility: adding up from 29 to 73, so 1+ 40 + 3 = 44.
- Place value: partitioning the 29, so 73 – 20 = 53 →53 – 3 = 50 →50 – 6 = 44.
When recording the strategies the students selected to use, ask: “What is it about the numbers that made you choose the strategy you used?” and “Which of these strategies is the most efficient? Why?” If the students have used place-value strategies to solve the problem, they may need to revise equal adjustments and rounding and compensating.
As well as presenting problems for the students to solve as equations, it is also important to present them as word problems – for example: “The children had to blow up 182 balloons to decorate the school hall. By playtime, they had blown up 26. How many more did they still need to blow up?”
Some Problem Sets
Record the problems on the board or modelling book in the horizontal form.
Set 1
45 + 58
67 + □ = 121
8 001 – 7 998
26 + □ = 52
81 – 67
456 + 144
789 – 85
□ + 58 = 189
33 + 809 + 67 + 91
Set 2
28 + 72
191 + □ = 210
7 001 – 21
39 + □ = 77
234 – 99
6091 + 109
2 782 – 15
□ + 123 = 149
616 + 407 – 16 + 93
Set 3
999 + 702
287 + □ = 400
2 067 – 999
45 + □ = 91
771 – 37 316 + 684
709 – 70
□ + 88 = 200
7 898 – 6 000 – 98 – 100
Set 4
38 + 128
14 + □ = 101
9 000 – 8 985
102 – □ = 34
800 – 33 78 + 124
4 444 – 145
□ + 8 = 1 003
4 700 – 498 + 200 –2
Set 5
405 + 58
880 + □ = 921
8789 – 7 678
80 – □ = 41
701 – 96 8 888 + 122
781 – 45
□ + 48 = 789
6 000 – 979 – 11 – 10
Missing Number Bingo
To practice counting forwards and backwards with decimal numbers. This is a whole class game but can be played in small group situations where they can take turns to call the numbers. Both cards can be played at the same time which caters for differing students’ needs.
order tenths (decimals)
Cards, 1 for each student (51KB)
Numbers to call (40KB)
My Decimal Number
In this activity students brainstorm different ways to represent decimal fractions. They will draw on their knowledge of decimal place value, addition and subtraction of decimals, and writing decimals in words and symbols.
represent decimal numbers in a variety of ways
For example 3.81 could be expressed as;
Common Multiples
This activity provides students with a fun, game context in which to practice finding common multiples of numbers. This activity builds knowledge to help develop multiplicative strategies.
Identify common multiples of numbers to 10.
Extension
You may like to get the students to make up their own game board, deciding which numbers would need to be on it for them to win. If you wanted to extend the game you could use 10 sided dice and construct a game board for that.
Mixing the methods - mental exercises for the day
Solve problems using a combination of addition, subtraction, multiplication and division mental strategies.
Number Framework Stage 6
At this stage, offering students a regular daily dose of mental calculation is strongly recommended. It is a good idea to record only one problem on the board or in the modelling book at a time and not allow the students to use pencil and paper. Make sure they all have time to solve each problem. Don’t allow early finishers to call out the answer.
For example, take the problem 73 – 29 = ?.
Prompt the students to look carefully at the numbers before deciding how they might solve this. The following are possible strategies:
When recording the strategies the students selected to use, ask: “What is it about the numbers that made you choose the strategy you used?” and “Which of these strategies is the most efficient? Why?” If the students have used place-value strategies to solve the problem, they may need to revise equal adjustments and rounding and compensating.
As well as presenting problems for the students to solve as equations, it is also important to present them as word problems – for example: “The children had to blow up 182 balloons to decorate the school hall. By playtime, they had blown up 26. How many more did they still need to blow up?”
Some Problem Sets
Record the problems on the board or modelling book in the horizontal form.
Set 1
45 + 58
67 + □ = 121
8 001 – 7 998
26 + □ = 52
81 – 67
456 + 144
789 – 85
□ + 58 = 189
33 + 809 + 67 + 91
Set 2
28 + 72
191 + □ = 210
7 001 – 21
39 + □ = 77
234 – 99
6091 + 109
2 782 – 15
□ + 123 = 149
616 + 407 – 16 + 93
Set 3
999 + 702
287 + □ = 400
2 067 – 999
45 + □ = 91
771 – 37 316 + 684
709 – 70
□ + 88 = 200
7 898 – 6 000 – 98 – 100
Set 4
38 + 128
14 + □ = 101
9 000 – 8 985
102 – □ = 34
800 – 33 78 + 124
4 444 – 145
□ + 8 = 1 003
4 700 – 498 + 200 –2
Set 5
405 + 58
880 + □ = 921
8789 – 7 678
80 – □ = 41
701 – 96 8 888 + 122
781 – 45
□ + 48 = 789
6 000 – 979 – 11 – 10
Target 15.287
To give students practice in adding numbers from one up to ones of thousands or decimal numbers from thousandths to ones. This is a whole class game but can be played in small group situations where they can take turns to roll the die. Both cards can be played at the same time which caters for differing students’ needs.
use their knowledge of the place value structure to add decimals together.
Transparent Counters
1 gameboard (47KB) per student
One 10 sided die
This game can be played simultaneously with Target 15 287, allowing for students of a range of abilities to participate.
Acknowledgement
This game of Target has been adapted from one originally made up by a group of South Auckland teachers.
Easy fraction game
To give students practise in adding fractions that match the descriptions eg. 1/8 + 1/4 ‘add to less than 1’. This can be used as a class starter or as an independent game.
add fractions with related denominators.
1 die numbered 1/2, 1/4, 3/4, 3/8, 5/8, 1/8.
A blank die with dots placed on and numbered, is useful as it can be used again with different numbers.
Photocopied sheets
Activity
Create A Question
There is a special number in each of these envelopes.
When you get your envelope, open it and find out what your number is.
This number is the solution to a maths problem that YOU make up.
What is your problem?
In this problem, students are challenged to create their own number problems. This can require a deeper understanding than solving a given problem.
Some students may simply suggest an equation. Some may be able to confidently embed an equation in a story context, and other students might readily suggest contextual problems that involve several steps, or a range of operations.
This open problem has students use their imaginations to create word problems of their own and to apply the mathematics that they are learning. You can adjust the difficulty of the problem by changing the numbers you place inside the envelopes.
A series of similar Number problems span Levels 1 to 5. These are You Be The Teacher, Level 1; Make Up Your Own, Level 2; Invent-A-Problem, Level 3; and Working Backwards, Level 5.
You may find that this serves as a useful assessment task.
The Problem
There is a special number in each of these envelopes.
When you get your envelope, open it and find out what your number is.
This number is the solution to a maths problem that YOU make up.
What is your problem?
Teaching sequence
There are many ways to have your students create their own problems for others to solve.
This is just one possible way to consider.
Solution
The solutions will depend on your class.