Math 1A Singapore-Other Methods of Addition-Chapter 3.3
Other Methods of Addition
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🐸🐸🐸🐸
4
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🐸
1 more
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4
+ 1 = 5
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🐸🐸🐸🐸
4
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🐸🐸
2 more
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4
+ 2 = 6
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🐸🐸🐸🐸
4
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🐸🐸🐸
3 more
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4 + 3 = 7
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1. Add 6 and 1.
Solution:
3,4,5,6,7,8,9,…….
Begin with 6 and count
on next 1 step: 7
We will get 7.
So, 6 + 1 = 7
2. Add 7 and 2.
Solution:
3,4,5,6,7,8,9,10…….
Begin with 7 and count
on next 2 steps: 8,
9
We will get 9.
So, 7 + 2 = 9
3. Add 4 and 3.
Solution:
3,4,5,6,7,8,9,10,11,…..
Begin with 4 and count on next 3 steps: 5,6,7.
We will get 7.
So, 4 + 3 = 7.
4. Complete the addition sentences.
(a)
4 + 0 = ?
5 + 0 = ?
8 + 0 = ?
(b)
5 + 1 = ?
7 + 1 = ?
9 + 1 = ?
(c)
3 + 2 = ?
6 + 2 = ?
8 + 2 = ?
(d)
5 + 3 = ?
6 + 3 = ?
7 + 3 = ?
Solution:
(a)
4 + 0 = 4
5 + 0 = 5
8 + 0 = 8
(b)
5 + 1 = 6
7 + 1 = 8
9 + 1 = 10
(c)
3 + 2 = 5
6 + 2 = 8
8 + 2 = 10
(d)
5 + 3 = 8
6 + 3 = 9
7 + 3 = 10
5. Complete the addition sentences.
(a) 1 + 🟦 = 10 (b)
2 + 🟦 = 10
(c) 3 + 🟦
= 10 (d) 4 + 🟦 = 10
(e) 5 + 🟦
= 10 (f) 6 + 🟦 = 10
(g) 7 + 🟦
= 10 (h) 8 + 🟦 = 10
(i) 9 + 🟦
= 10 (j) 10 + 🟦 = 10
Solution:
(a) 1 + 9 = 10 (b) 2 + 8 = 10
(c) 3 + 7 = 10 (d) 4 + 6 = 10
(e) 5 + 5 = 10 (f) 6 + 4 = 10
(g) 7 + 3 = 10 (h) 8 + 2 = 10
(i) 9 + 1 = 10 (j) 10 + 0 = 10
6. Which rats
will each cat catch?
Solution:
Brown cat catches only tens.
So, Brown cat catches 4+6,
8+2, 3+7, 7+3, 2+8, 9+1, 5+5, 6+4 marked rats.
Yellow cat catches only
nines.