Math 1A Workbook Exercise 25-30 Singapore Part 6
1A Workbook Exercise 25-30
Exercise 25
1. Complete the number sentences.
(a)
5 + 1 = ⬜.
1
+ 5 = ⬜.
6
– 5 = ⬜.
6 – 1 = ⬜.
Solution:
5
+ 1 = 6.
1
+ 5 = 6.
6
– 5 = 1.
6
– 1 = 5.
(b)
4
+ 3 = ⬜.
3
+ 4 = ⬜.
7
– 4 = ⬜.
7
– 3 = ⬜.
Solution:
4
+ 3 = 7.
3
+ 4 = 7.
7
– 4 = 3.
7
– 3 = 4.
2. Write 2 (two) addition sentences and 2 (two) subtraction sentences for each picture.
5 + 2 = 7.
2 + 5 = 7.
7 – 2 = 5.
7 – 5 = 2
6 + 4 = 10.
4 + 6 = 10.
10 – 6 = 4.
10 – 4 = 6.
6 + 3 = 9.
3 + 6 = 9.
9 – 3 = 6.
9 – 6 = 3.
Exercise 26
1. Write ‘+’ or ‘-’ in each ⚪.
3 ⚪ 1 = 2.
2 ⚪ 2 = 0.
3 ⚪ 2 = 5.
5 ⚪ 1 = 4.
4 ⚪ 3 = 1.
1 ⚪ 3 = 4.
Solution:
3 – 1 = 2.
2 – 2 = 0.
3 + 2 = 5.
5 – 1 = 4.
4 – 3 = 1.
1 + 3 = 4.
2. Use the numbers and signs to
write a number sentence.
(a) 3,10,7,=,-
(b) 3,7,4,=,+
(c) 6,6,0,=,+
(d) 7,9,2,=,-
(e) 5,3,8,=,-
Solution:
(a) 10 – 7 = 3.
(b) 3 + 4 = 7.
(c) 0 + 6 = 6.
(d) 9 – 7 = 2.
(e) 8 – 5 = 3.
Exercise 27
1. Count backwards to subtract.
(a) 6 – 2 = ⬜.
(b)
8 – 3 = ⬜.
(c)
7 – 1 = ⬜.
(d)
10 – 3 = ⬜.
Solution:
(a)
6 – 2 = 4.
[ 2←3←4←5←6; Start count with 7
and count backwards for 2 steps ]
(b) 8 – 3 = 5.
[ 3←4←5←6←7←8; Start count with 8
and count backwards for 3 steps ]
(c)
7 – 1 = 6.
[ 3←4←5←6←7; Start count with 7
and count backwards for 1 step ]
(d)
10 – 3 = 7.
[ 3←4←5←6←7←8←9←10; Start count with
10 and count backwards for 3 steps ]
2. Subtract 1 from
each number.
6
Solution:
6
– 1 = 5.
4
– 1 = 3.
8
– 1 = 7.
3. Subtract 2 from
each number.
7
Solution:
7
– 2 = 5.
5
– 2 = 3.
9
– 2 = 7.
4. Subtract 3 from
each number.
5
Solution:
5
– 3 = 2.
8
– 3 = 5.
10
– 3 = 7.
Exercise 28
1. Subtract. Then
color in this way.
0
– Yellow.
1
– Red.
2
– Green.
Others
– Blue.
Solution:
[The
solution is shown as a table basis.]
|
5 – 1 = 4 |
3 – 0 = 3 |
8 – 8 = 0 |
|
5 – 2 = 3 |
8 – 7 = 1 |
7 – 2 = 5 |
|
6 – 6 = 0 |
10 – 10 = 0 |
8 – 1 = 7 |
|
5 – 4 = 1 |
6 – 5 = 1 |
3 – 3 =0 |
|
7 – 7 = 0 |
9 – 8 = 1 |
4 – 2 = 2 |
|
2 – 0 = 2 |
9 – 2 = 7 |
3 – 2 = 1 |
|
9 – 7 = 2 |
10 – 1 = 9 |
10 – 8 = 2 |
|
10 – 9 = 1 |
5 – 3 = 2 |
8 – 2 = 6 |
|
7 – 5 = 2 |
9 – 1 = 8 |
7 – 2 = 5 |
Exercise 29
1. Cross out (❌ ) the ducks
that do not belong to the house.
Solution:
Click Here for the solution.
Exercise 30
1.
🦆 🦆 🦆 🦆 🦆
🦆 🦆
How many ducks are there altogether?
4 ⚪ 3 = ⬜.
There are ⬜ ducks altogether.
Solution:
4 + 3 = 7.
There are 7 ducks altogether.
2.
7 ⚪ 4 = ⬜.
⬜ oranges are left.
Solution:
7 – 4 = 3.
3 oranges are left.
3.
👫🕴👫🕴🕴 👫🕴
How many children are there altogether?
7 ⚪ 3 = ⬜.
There are ⬜ children altogether.
Solution:
7 + 3 = 10.
There are 10 children altogether.
4.
10 ⚪ 6 = ⬜.
⬜ eggs are used.
Solution:
10 – 6 = 4.
4 eggs are used.
5.
⚽ ⚽ ⚽ ⚽ ⚽ ⚽
How many small balls are there?
6 ⚪ 3 = ⬜.
There are ⬜ small balls.
Solution:
6 – 3 = 3.
There are 3 small balls.
6.
🦋🦋🦋 🦋
How many butterflies are there altogether?
3 ⚪ 1 = ⬜.
There are ⬜ butterflies altogether.
Solution:
3 + 1 = 4.
There are 4 butterflies altogether.