Math 1A Workbook Exercise 17-20 Singapore Part 4
1A Workbook Exercise 17-20
Exercise 17
1. Draw and complete the number sentences.
(a)
5 balloons: 🎈.🎈.🎈.🎈.🎈.
Draw 2 more balloons:
5 + 2 = ?
Solution:
2 balloons: 🎈. 🎈.
5 + 2 = 7.
(b) 4 birds: 🐦.🐦.🐦.🐦.
Draw 3 more birds.
4 + 3 = ?
Solution:
3 birds: 🐦.🐦.🐦.
4 + 3 = 7.
(c) 3 umbrellas: ☂.☂.☂.
Draw 1 more umbrella.
3 + 1 = ?
Solution:
1 umbrella: ☂.
3 + 1 = 4.
(d) 5 lollipops: 🍭.🍭.🍭.🍭.🍭.
Draw 2 more lollipops.
5 + 2 = ?
Solution:
2
lollipops: 🍭.🍭.
5 + 2 = 7.
2.
There are 7 flowers in the wave. Add 2 more. There will be ⬜ flowers
in the vase.
Solution:
7 +
2 = 9.
There
will be 9 flowers in the vase.
3. There
are 6 oranges in the bowl. Add 4 more. There will be ___ oranges in the bowl.
Solution:
6 +
4 = 10
There
will be 10 oranges in the bowl.
Exercise 18
1.
Count on to add.
(a)
3 + 2 = ⬜. (b) 8 + 1 = ⬜.
(c)
4 + 2 = ⬜. (d) 7 + 3 = ⬜.
Solution:
(a)
3→4→5→6→7→8……
[Count starts on 3 and count on next 2 steps]
3 + 2 = 5.
(b)
8→9→10→11……
[Count starts on 8 and count on next 1 step]
8 + 1 = 9.
(c)
4→5→6→7→8……
[Count starts on 4 and count on next 2 steps]
4 + 2 = 6.
(d)
7→8→9→10→11→12……
[Count starts on 7 and count on next 3 steps]
7 + 3 = 10
2. Add 1 to each number.
6, 3, 4
Solution:
6 + 1 = 7.
3 + 1 = 4.
4 + 1 = 5.
3. Add 2 to each number.
8, 5, 7
Solution:
8 + 2 = 10.
5 + 2 = 7.
7 + 2 = 9.
4. Add 3 to each number.
3, 6, 7
Solution:
3 + 3 = 6.
6 + 3 =9.
7 + 3 = 10.
Exercise 19
1. Add. Then color in this way.
10 – red.
9 – blue.
8 – brown.
7 – green.
Solution:
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8+1=9
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7+2=9
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7+0=7
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6+1=7
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|
4+5=9
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5+2=7
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|
4+3=7
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3+4=7
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|
5+4=9
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7+3=10
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4+6=10
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9+0=9
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9+1=10
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6+4=10
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3+7=10
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8+2=10
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5+3=8
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0+10=10
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1+9=10
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7+1=9
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10+0=10
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2+7=9
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2+6=8
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3+6=9
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4+4=8
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0+8=8
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6+2=8
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3+5=8
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Exercise 20
1. Fill in the blanks (as per the below picture)
(a) There are 5 helicopters. ___ fly away. ___ helicopters are
left.
(b) There are 6 children. ___ walk away. ___ children are left.
(c) There are 7 boxes. I take away ___. ___ boxes are left.
(d) There are 9 beads. I take away ____. ___ beads are left.
Solution:
(a) There are 5 helicopters. 2 fly away. 3 helicopters are left.
(b) There are 6 children. 2 walk away. 4
children are left.
(c) There are 7 boxes. I take away 1. 6
boxes are left.
(d) There are 9 beads. I take away 4. 5
beads are left.
2. Fill in the blanks (as per picture).
(a) ___ fish are left.
(b) ___ carts are left.
(c) ___ cakes are left.
(d) ___ balloons are left.
Solution:
(a) 2 fish are left.
(b) 0 carts are left.
(c) 4 cakes are left.
(d) 6 balloons are left.