# Jumping the number line – decimal fractions (hundredths)

### Teacher’s Notes

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

### Number Framework domain and stage:

Addition and subtraction, stage 7, advanced multiplicative

### Curriculum Reference:

Number, level 4

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

- Explain how to find the compatible numbers to 100
- Use the strategy jumping the number line with whole numbers (book 5 page 33)
- Explain the role of the decimal point in a decimal
- Identify the place value of the tenths hundreds and thousandths columns, and explain why they are named thus
- Make combinations of tenths and hundredths that add to one

### During these activities, students will meet:

- Using jumping the number line strategy to add decimal fractions (tenths and hundredths).

This may be done either using the number line or with written recording of identified ‘mental jumps’

### Background

These exercises have been set up in the following way.
Exercise 1: adding on from a whole number

Exercise 2: jumping up to a whole number and then adding on using three step method

Exercise 3: using two steps only – hundredths (between 0.01 and 0.09) added onto a tenths number

Exercise 4: using two steps only – hundredths (between 0.01 and 0.09) added onto a hundredths number

Exercise 5: using two steps only – hundredths (between 0.11 and 0.29) added onto a tenths number

Exercise 6: using two steps only – hundredths (between 0.11 and 0.29) added onto a hundredths number

Exercise 7: a mixture

### Written recording

Written recording of mental strategies (that is, how you thought through the problem) is important for developing sound assessment skills as it allows others to follow your reasoning and allows you to have a visual check for accidental errors. It is also something that develops over time, and needs to be discussed regularly with students. Exercises 5, 6 and 7 stress that students should solve the problems mentally, but record enough to show what they have done. Discussing or eliciting different ways of doing this is therefore an important activity, which you may choose to run either before or after setting students to work on this exercise