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To be able to add two 2-digit numbers (with exchange)
Success criteria:
✓ I can add tens and ones to combine two 2-digit numbers (with exchanging)
✓ I can explain my reasoning when adding tens and ones to combine two 2-digit numbers (with exchanging)
To be able to add two 2-digit numbers (with exchange)
Starter:
What’s the same? What’s different?
Explain your answer.
+
2
2
4
5 +
3
1
3
6
To be able to add two 2-digit numbers (with exchange)
Starter:
What’s the same? What’s different?
The parts are different, but the whole amounts are the same: 49.
+
2
24
4
59
+
3
14
3
69
To be able to add two 2-digit numbers (with exchange)
Teaching Time:
Building on yesterday’s learning you are looking at adding two 2-digit numbers today. However todayyou will need to exchange. We exchange any time we have a number higher than 9 in a place value column. For example, 10 or higher is not allowed in the ones column. To understand this concept, the column addition has been broken into extra steps than yesterday.
+
+
22
57
5 ones + 7 ones = 12 ones2 tens + 2 tens = 4 tens4 tens + 12 ones = 52
25 + 27 = 52
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
22
57
5 ones + 7 ones = 12 ones2 tens + 2 tens = 4 tens4 tens + 12 ones = 52
25 + 27 = 52
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
22
1
57
2
5 ones + 7 ones = 12 ones2 tens + 2 tens = 4 tens4 tens + 12 ones = 52
25 + 27 = 52
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
22
1
4
57
2
0
5 ones + 7 ones = 12 ones2 tens + 2 tens = 4 tens4 tens + 12 ones = 52
25 + 27 = 52
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
22
1
4
57
2
0
5 ones + 7 ones = 12 ones2 tens + 2 tens = 4 tens4 tens + 12 ones = 52
25 + 27 = 52
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
22
1
45
57
2
02
5 ones + 7 ones = 12 ones2 tens + 2 tens = 4 tens4 tens + 12 ones = 52
25 + 27 = 52
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
32
68
6 ones + 8 ones = 14 ones3 tens + 2 tens = 5 tens5 tens + 14 ones = 64
36 + 28 = 64
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
32
1
68
4
6 ones + 8 ones = 14 ones3 tens + 2 tens = 5 tens5 tens + 14 ones = 64
36 + 28 = 64
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
32
1
5
68
4
0
6 ones + 8 ones = 14 ones3 tens + 2 tens = 5 tens5 tens + 14 ones = 64
36 + 28 = 64
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
32
1
5
68
4
0
6 ones + 8 ones = 14 ones3 tens + 2 tens = 5 tens5 tens + 14 ones = 64
36 + 28 = 64
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
32
1
56
68
4
04
6 ones + 8 ones = 14 ones3 tens + 2 tens = 5 tens5 tens + 14 ones = 64
36 + 28 = 64
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
43
78
7 ones + 8 ones = 15 ones4 tens + 3 tens = 7 tens7 tens + 15 ones = 85
47 + 38 = 85
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
43
1
78
5
7 ones + 8 ones = 15 ones4 tens + 3 tens = 7 tens7 tens + 15 ones = 85
47 + 38 = 85
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
43
1
7
78
5
0
7 ones + 8 ones = 15 ones4 tens + 3 tens = 7 tens7 tens + 15 ones = 85
47 + 38 = 85
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
43
1
7
78
5
0
7 ones + 8 ones = 15 ones4 tens + 3 tens = 7 tens7 tens + 15 ones = 85
47 + 38 = 85
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
43
1
78
78
5
05
7 ones + 8 ones = 15 ones4 tens + 3 tens = 7 tens7 tens + 15 ones = 85
47 + 38 = 85
To be able to add two 2-digit numbers (with exchange)
Challenge 1:
Complete the following:
+
+
53
89
7 ones + 8 ones = 17 ones5 tens + 3 tens = 8 tens8 tens + 17 ones = 97
58 + 39 = 97
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
32
97
t ens ones
To be able to add two 2-digit numbers (with exchange)
Talking Time:
Complete the following:
+
+
32
1
56
97
6
06
tens ones
To be able to add two 2-digit numbers (with exchange)
Challenge 2:
Find the total for 29 and 59.
+
+
52
99
tens ones
To be able to add two 2-digit numbers (with exchange)
Challenge 3:
Complete the word problems below.
a) Miss Jones’ class have 43 glue sticks, Mr Patel’s class have 18 glue sticks.How many glue sticks do both classes have altogether?
b) Miss Begum’s class have 49 glue sticks, Miss Jones is still holding on tightly to her 43 glue sticks.How many glue sticks to both classes have altogether?
To be able to add two 2-digit numbers (with exchange)
Extra Challenge 1:
Create as many addition calculations as you can think of that require an exchange of ones for a ten and result in a total that is less than 100 and has a 3 in the ones column.
An example has been provided.
To be able to add two 2-digit numbers (with exchange)
Extra Challenge 2:
How many ways can you find to complete the addition calculation below?
What do all the pairs of missing numbers have in common? Explain your answer.
To be able to add two 2-digit numbers (with exchange)
Challenge 1 Answers:
Complete the following:
+
+
53
1
89
89
7
07
7 ones + 8 ones = 17 ones5 tens + 3 tens = 8 tens8 tens + 17 ones = 97
58 + 39 = 97
To be able to add two 2-digit numbers (with exchange)
Challenge 2 Answers:
Find the total for 29 and 59.
+
+
52
1
78
99
8
08
tens ones
To be able to add two 2-digit numbers (with exchange)
Challenge 3 Answers:
Complete the word problems below.
a) Miss Jones’ class have 43 glue sticks, Mr Patel’s class have 18 glue sticks.How many glue sticks do both classes have altogether?43 + 18 = 61
b) Miss Begum’s class have 49 glue sticks, Miss Jones is still holding on tightly to her 43 glue sticks.How many glue sticks to both classes have altogether?49 + 43 = 92
To be able to add two 2-digit numbers (with exchange)
Extra Challenge 1 Answer:
Create as many addition calculations as you can think of that require an exchange of ones for a ten and result in a total that is less than 100 and has a 3 in the ones column.
An example has been provided.
Multiple solutions up to 47 + 46 = 93 (or similar).
To be able to add two 2-digit numbers (with exchange)
Extra Challenge 2 Answers:
How many ways can you find to complete the addition calculation below?
It could be 26 + 29 27 + 28, 28 + 27, or 29 + 26.
The ones digit are all number bonds to 15, the amount required to be added to 2 lots of 2 tens making 4 tens (or forty) to make 55.
To be able to add two 2-digit numbers (with exchange)
Evaluation:
Do you agree?Explain your answer.
It is just as easy to add 11 + 19 as it is to
add 17 + 13.
To be able to add two 2-digit numbers (with exchange)
Evaluation:
It is easy to add two lots of 1 ten together – making 2 tens or twenty.Then, we should recognise that the pairs of digits in the ones columns in both number sentences are number bonds to ten, which means both exchange to form a third ten, making a total of 30 in both instances.
It is just as easy to add 11 + 19 as it is to
add 17 + 13.
To be able to add two 2-digit numbers (no exchange)
Success criteria:
✓ I can add tens and ones to combine two 2-digit numbers (with exchanging)
✓ I can explain my reasoning when adding tens and ones to combine two 2-digit numbers (with exchanging)
Year 2 - Autumn Block 2 – Addition and Subtraction - Lesson 12 – To be able to add two 2-digit numbers (with exchange)
