Year 5 Spring Teaching Sequence 7

Activity 1

Objectives: Derive quickly pairs of two-digit numbers with a total of 100, e.g. 68 and 32.

Level of difficulty: Easy

· Remind the children of strategies to find pairs of two-digit numbers that make 100.

· Tens total ninety, units total ten,

e.g. 86 + 14

90 + 10

· Divide the class into pairs ready to play ‘Totals 100 Tennis’.

· Player One serves by calling a two-digit number, e.g. 72.

· Player Two responds with the number needed to make it to 100.

· If correct Player Two calls another number.

· Now it’s Player One’s turn to respond.

· If a player responds with the incorrect number or hesitates the point goes to the other player.

Extension:

· Play with pairs to 1000.

Activity 2

Objectives: Add and subtract any pair of two-digit numbers

Resources: Sheets of hexagonal grid paper

Level of difficulty: Medium

· Provide pairs of children with hexagonal grid paper.

· The children should work to fill a 10x10 section with two-digit numbers.

· Tell the children that they are going to play Blockbusters; Player One will attempt to work from top to bottom, Player Two left to right.

· To claim a hexagon a player must add the number in that hexagon to the number in any adjoining hexagon. They must get the answer correct! (Could check with a calculator).

· Players should colour each hexagon they claim.

· The players take it in turns to claim hexagons until one player creates a continuous line across the board.

An image search for Hexagonal Grid Paper results in many printable examples.

· Play again asking children to subtract the numbers in adjoining hexagons.

Activity 3

Objectives: Derive quickly pairs of two-digit numbers with a total of 100, e.g. 68 and 32

Resources: 0-9 dice, whiteboards, pens

Level of difficulty: Medium

· Provide groups of children with a 0-9 dice or a set of 0-9 cards shuffled in a pile face down.

· Tell them that the dice should be rolled four times (or four cards taken) and that they should all record the digits on their whiteboards.

· Children should then use only these digits in any order to create two, 2-digit numbers. Each digit can only be used once,

e.g. If 3 2 7 and 1 are rolled a player could create 21 and 73.

· These two-digit numbers should then be added or subtracted.

e.g. 73 + 21 = 94

· The player with the answer closest to 0 or 100 wins a point.

· Discuss with the chn how they can calculate which number is closest to the target.

o How can you increase your chances of being closest to the target?

o How might estimating be a useful strategy?

Activity 4

Objectives: Derive pairs of two-digit numbers that total 100

Resources: Class set of calculators, whiteboards, and IWB calculator

Level of difficulty: Medium

· The activity is ‘Make 100’ and these are the rules;

o You cannot press 0

o You can only press + (not - x or ÷)

o You must press 6 keys exactly

o For example 4 2 + 5 8 =

· Work in pairs to find as many pairs of two-digit numbers that total 100 in 5 minutes as possible.

· Take feedback encouraging children to say complete number sentences

o Here’s one that I did 32 + 78 = 100. Is that OK?

· Take the opportunity to confirm that the multiples of ten must sum to 90 rather than 100, the source of the common error.

Activity 5

Activity 5 is no longer relevant and has been removed from this document.