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Level Four > Number and Algebra

Keywords:
Specific Learning Outcomes:

Solve problems that involve adding and subtracting decimals.

Description of mathematics:

Number Framework Stage 7

Required Resource Materials:
Sets of ten connected unilink cubes wrapped in paper
Activity:

#### Using Materials

Problem: Work out 3.9 + 2.4

Students model 3.9 + 2.4 as 3 wrapped bars (wholes) and 9 small pieces (tenths) and as 2 wrapped bars and 4 small pieces. Collecting them gives 5 wholes and 13 tenths. By the canon of place value, 10 tenths are rewrapped to give 1 whole.

So 3.9 + 2.4 = 6.3

#### Using Materials, Using Imaging, and Using Number Properties

When teachers make up their own examples, they should generally make sure that there are 10 or more tenths in the addition so that 10 tenths has to be swapped for 1 whole. So 3.3 + 1.9 is suitable, but 3.4 + 4.4 is not. The teacher can select problems from the set below for any stage.

3.9 + 2.4      2.6 + 1.6         1.4 + 0.8        3.5 + 2.5

0.6 + 1.7      5.8 + 0.8         2.2+ 1.9         4.2 + 2.3

2.9 + 1.9      0.6 + 1.6         3.2 + 0.8        2.4 + 1.5

10.4 + 10.9         18.5 + 1.7            0.4 + 20.8                   15.2 + 2.3

## Percentage Increases & Decreases in One Step

Estimate and find percentages of whole number and decimal amounts.

## Reverse Percentage Problems

Estimate and find percentages of whole number and decimal amounts.

## Comparing Chalk and Cheese

convert unlike units in order to add and subtract them

## Dallying with Decimals

This is a level 4 number activity from the Figure It Out series. It relates to Stage 7 of the Number Framework.

## Target Time

This is a level 4 number activity from the Figure It Out series. It relates to Stage 7 of the Number Framework.