# Compatible decimal fractions Teacher’s Notes

These exercises and activities are for students to use independently of the teacher to practice and develop their number properties.

Number, level 3

### Numeracy Project book reference:

These activities can be used to follow teaching episodes based on Book 5, page 26. They are to be used with students who are able to use the associated number properties.

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

• Identify the facts to 10
• Explain place value with decimals
• know combinations of tenths that add to one
• Use the idea of compatible numbers to add whole numbers

### During these activities, students will meet:

Using compatible numbers to solve addition problems with decimal fractions (tenths) (Exercises 1-5)
Using compatible numbers to solve subtraction problems with decimal fractions (tenths) (Exercise 6)

### Background

The exercises have been set up in the following way.
Exercise 1: Identifying tenths that add to one.
Exercise 2: Tenths that add to one and more or less than one.
Exercises 3 – 5 are problems requiring addition of decimal fractions (tenths) using compatible numbers strategy.
Exercise 3: All numbers are less than one and students make numbers up to one.
Exercise 4: Compatible numbers include one number less than one and one number greater than one.
Exercise 5: Compatible numbers could both be greater than one.
Exercise 6: Using compatible numbers in subtraction (decimal fractions).