# Adding in Parts

Teacher’s Notes

These exercises and activities are designed for students to use independently to practise number properties.

### Number Framework domain and stage:

Addition and Subtraction – Advanced additive to advanced multiplicative

### Curriculum reference:

Number, level 3

### Numeracy Project book reference:

These activities can be used to follow the teaching episodes based on Book 5 pg 29 and are for those students who are able to use the associated number properties.

### Prior knowledge. Students should be able to:

- split a whole number into parts eg. 8 = 5 + 3, 27 = 25 + 2
- make numbers up to a tidy number
- add and subtract tenths to make a decimals number into a whole number

### During these activities students will meet:

- addition of whole numbers up to three digits
- addition of decimals
- use of equals
- use > and <

### Background:

The exercises have been set up in the following way:

Exercise 1: Adding on to a two digit number by splitting one number into parts.

Exercise 2: Adding on to a three digit number by splitting one number into parts.

Exercise 3: Adding tenths to get a whole number.

Exercise 4: Adding decimal numbers with one decimal place by making one number into a whole number and adjusting the other number.

Exercise 5: Recognising true statements based on adjusting one number up and the other number down.

Exercise 6: Finding the missing number to make a true statement based on adjusting one number up and the other number down.

Exercise 7: Students write their own true statement and describe the relationship between the new numbers.

Exercise 8: Students explain relationships based on adjusting numbers up and/or down. This needs to be followed by class discussion.

Exercise 9: Generalising the relationship by using a variable with a number

### Practice exercises with answers:

### Related activities and web links:

Addition Squares:PDF (81KB) or Word (93KB)

There are two addition squares. Students cut out the nine squares and rearrange them to form a 3 by 3 square. Where two squares are touching the expressions on the sides must be equivalent.