# 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.**

**Solution:**

5 + 2 = 7.

2 + 5 = 7.

7 – 2 = 5.

7 – 5 = 2

**Solution:**

6 + 4 = 10.

4 + 6 = 10.

10 – 6 = 4.

10 – 4 = 6.

**Solution:**

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.