Year 1 Maths 7.1.21

Place Value

Say 1 more and 1 less than a 2-digit number

Objectives Day 2 Find one more and one less than any 2-digit number.

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1

Year 1

Day 2: Find one more and one less than any 2-digit number. +1

23 24

23 + = 1 24

Now Where Lookcount atisthis 23 on Now count on one. on the Where this beaded do one.

Where do calculation. we line? land? we land?

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2

Year 1

Day 2: Find one more and one less than any 2-digit number.

Look Look at at the the rest rest of of these these calculations. calculations.

Work Work through through each each of of these these calculations: calculations: ask ask children children to to find find the the first first number number on on the the beaded beaded line line before before counting counting on on or or back back one one bead. bead.

Draw Draw the the hop hop and and label label +1 +1 or or -1.

-1.

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23 34 29 99

3

+ + + +

1 1 1 1

24 67 60 80

– – – –

1 1 1 1

Year 1

Day 2: Find one more and one less than any 2-digit number.

23 + 1 = 24 24 - 1 = 23

What if we took We had had 23 23 theWe 1 away again.

Back on 23! then then Where would we added 1. added 1. land?

Use Use numbers numbers 23 23 or or 24 24 to to fill fill the the blanks blanks in in these these sentences. sentences.

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24 is one more than 23

4

23 is one less than 24

Day 2: Find one more and one less than any 2-digit number.

46 + 1 = 47 47 - 1 = 46

What if we We had 46 We hadtook 46 the 1 away again. then then Back on 46!

Where would added 1. added 1.we land?

Fill Fill in in the the blanks blanks using using 46 46 or or 47.

47.

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47 is one more than 46

5

46 is one less than 47

Year 1

Investigation: Adult Sheet

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6

Year 1

Investigation: Child Sheet

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7

Year 1

Place Value

Say 1 more and 1 less than a 2-digit number

Objectives Day 1 Find one more and one less than any 2-digit number.

Day 2 Find one more and one less than any 2-digit number.

© hamilton-trust.org.uk

8

Year 1

Problem Problem solving solving and and reasoning reasoning questions questions What What are are the the numbers numbers after… after… (a) 46? (b) 59? (a) 46? (b) 59? (c) (c)

80?

80?

What What are are the the numbers numbers before… before… (a) 81? (b) 70? (a) 81? (b) 70? (c) (c)

39?

39?

Mystery Mystery number number II add add one one to to my my number number and and get get 75.

75.

What What isis my my number? number?

Jim Jim takes takes one one away away from from his his number number and and gets gets 52.

52.

What What isis Jim’s Jim’s number? number?

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9

Year 1

Problem Problem solving solving and and reasoning reasoning questions questions answers answers What are the numbers before…

What are the numbers after…

(a)

81?

80

(a)

46?

47

(b)

70?

69

(b)

59?

60

(c)

39?

38

(c)

80?

81

Some children may find (b) tricky, i.e. a number ending in 9, as the 10s digit changes in the answer. Others may find (c) tricky as the next number is across the other side of the 100-square.

Mystery number I add one to my number and get 75.

What is my number? 74 Jim takes one away from his number and gets 52. What is Jim’s number? 53 If children are struggling with the vocabulary, model using a 1-100 number square and ask children to make up similar questions for each other.

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10

Year 1