Download KU Add 4 Decimals 2 Session plan

Addition 4
Decimals 2
Objectives

Use knowledge of pairs of numbers with one decimal place with a
total of 1 to work out what needs to be added to make the next
whole number or to make 10

Use knowledge of pairs of single-digit whole numbers to add
multiples of 0.1, e.g. use 5 + 7 to find 0.5 + 0.7

Apply strategies used for adding pairs of whole numbers to adding
numbers with one or two decimal places

Use pairs to 10 and 100 to find what needs to be added to number
with two decimal places to make a given whole number
For this unit you will need:
stopwatch or clock/watch with a second hand, Number facts grid at
http://www.topmarks.co.uk/Flash.aspx?f=NumberFactsGridv2
Watch out for pupils who:

have difficulty when the addition of numbers with two place
decimals necessitates crossing through the next multiple of 1, e.g.
add 0.7 and 0.5 and write 0.12;

think that 0.64 goes with 1.44 for example to make the next whole
as they look for both tenths and hundredths with a total of 10;

have difficulty when the addition means passing through the next
multiple of 1, e.g. 7.6 + 2.7, 8.4 + 1.7; give more practice counting
in 0.1s through multiples of 1;

try to keep all the steps in their head and lose track; encourage
them to use jottings, modelling how to use these if necessary.
HSNP © Hamilton 2013
Keeping Up Term 2
Addition 4
Session 1
Objective: Use knowledge of pairs of numbers with one decimal place with
a total of 1 to work out what needs to be added to make the next whole
number or to make 10
Teacher input with whole class
 Play ‘I say, you say’ to make 1. I say 0.6. Pupils respond we say 0.4.
Repeat with 0.1, 0.2…0.9 in random order, at a brisk pace.
 Draw a four-by-three grid on the board. Write a number with one
decimal place less than 10 in each space. Pupils copy the grid but as
you write each number they write the decimal needed to make the
next whole number, e.g. you write 4.6, they write 0.4.
4.6
7.8
5.2
6.4
8.5
4.9
7.3
6.1
8.7
2.4
6.5
3.8




Check answers for each cell.
Point to the first number, e.g. 4.6 and ask how much needs to be
added to make 10. Draw out adding 0.4 to make 5, and then 5 to make
10, i.e. 5.4.
Pupils re-draw the grid and this time write the number needed to
make 10.
Check answers for each cell.
Paired pupil work
 Challenge pupils to work in pairs to write as many pairs of numbers
with one decimal place, with a total of 10 as they can in two minutes.
 Pairs swap with another pair to mark each others’.
 Did anyone write more than 20 correct sums?
HSNP © Hamilton 2013
Keeping Up Term 2
Addition 4
Session 2
Objectives: Use knowledge of pairs of single-digit whole numbers to add
multiples of 0.1, e.g. use 5 + 7 to find 0.5 + 0.7; Apply strategies used for
adding pairs of whole numbers to adding numbers with one decimal place
Teacher input with whole class
 Write numbers 0.7, 0.8, 0.9, 1, 1.1…1.8 on the board. Pupils choose six
numbers to write on their whiteboards.
 Call out additions of single-digit decimals, e.g. 0.7 + 0.8, keeping a
record of each, if pupils have the answer they ring it. The first to ring all
six numbers wins. Check their answers as a class.
 Write the following additions on the board: 4.3 + 1.9, 3.7 + 3.7, 4.5 +
0.8, 9.4 + 2.8, 4.6 + 4.5. Point to each in turn and ask pupils to discuss in
pairs how they would find the total. Take feedback. Draw out using
number facts, doubles and near doubles, e.g. double 45 is 90, so 46 +
45 = 91. 4.6 + 4.5 will be a tenth of 91, i.e. 9.1. Draw out using
partitioning and recombining, e.g. find 94 + 27 by adding 90 and 20, 4
and 7, then adding 110 and 11. Pupils may do this then divide by 10 to
work out 9.4 + 2.7, or add the whole numbers, then the tenths and
recombine, i.e. 9 + 2 = 11, 0.4 + 0.7 = 1.1, 11 + 1.1 = 12.1.
Paired pupil work
 Use Number facts grid at
http://www.topmarks.co.uk/Flash.aspx?f=NumberFactsGridv2,
choosing U.t + U.t crossing 10s. Click on all the yellow cells. Explain
how to add numbers to create totals in the grid, clicking on the first
white cell to show this. Pupils copy and complete the grid. Click on
each cell so that pupils can check their answers.
HSNP © Hamilton 2013
Keeping Up Term 2
Addition 4
Session 3
Objective: Use pairs to 10 and 100 to find what needs to be added to
number with two decimal places to make a given whole number
Teacher input with whole class
 Play ‘I say, you say’ to make £1. I say 35p. Pupils respond we say 65p,
i.e, the amount needed to make £1. Repeat with other multiples of 5,
then other two-digit numbers.
Individual practice
 Pupils write as many pairs of two-place decimals with a total of 1 as
they can in two minutes, e.g. 0.72 + 0.28.
Teacher input with whole class
 Draw a four-by-three grid on the board. Write an amount of money
less than £10 in each space. Pupils copy the grid but as you write each
amount they write the amount needed to make the next whole pound,
e.g. you write £2.78, they write 22p.
£2.78
£3.67
£6.54
£4.65
£9.48
£1.14
£6.75
£8.88
£5.43
£2.15
£7.93
£8.29
Paired pupil work
 Pupils each write the digits 0 to 9 on a piece of paper. They take it in
turns to roll the dice three times to generate a price, e.g. roll 6, 5 and 8
to generate £6.58. They work out how much is needed to make the
next whole pound and cross out the digits in their list. They carry on
taking turns until one pupil has crossed out all digits to win.
HSNP © Hamilton 2013
Keeping Up Term 2