Let's solve each problem step by step using
bar modelling to find the missing number that makes the total
1000.
We are given two numbers in each problem, and we need to find the third number so that their sum is 1000.
---
1. 200 + 300 + ? = 1000
- Add the known numbers:
$ 200 + 300 = 500 $
- Subtract from 1000:
$ 1000 - 500 = 500 $
✔ Answer: 500
---
2. 300 + 500 + ? = 1000
- $ 300 + 500 = 800 $
- $ 1000 - 800 = 200 $
✔ Answer: 200
---
3. 150 + 250 + ? = 1000
- $ 150 + 250 = 400 $
- $ 1000 - 400 = 600 $
✔ Answer: 600
---
4. 250 + 350 + ? = 1000
- $ 250 + 350 = 600 $
- $ 1000 - 600 = 400 $
✔ Answer: 400
---
5. 275 + 225 + ? = 1000
- $ 275 + 225 = 500 $
- $ 1000 - 500 = 500 $
✔ Answer: 500
---
6. 365 + 235 + ? = 1000
- $ 365 + 235 = 600 $
- $ 1000 - 600 = 400 $
✔ Answer: 400
---
7. 449 + 351 + ? = 1000
- $ 449 + 351 = 800 $
- $ 1000 - 800 = 200 $
✔ Answer: 200
---
8. 372 + 328 + ? = 1000
- $ 372 + 328 = 700 $
- $ 1000 - 700 = 300 $
✔ Answer: 300
---
✔ Final Answers:
| Problem | Missing Number |
|--------|----------------|
| 1 | 500 |
| 2 | 200 |
| 3 | 600 |
| 4 | 400 |
| 5 | 500 |
| 6 | 400 |
| 7 | 200 |
| 8 | 300 |
---
🔍 Explanation (Bar Modelling):
The bar model shows:
- A long bar representing
1000
- Divided into three parts: two known values and one unknown
- The unknown part is the
difference between 1000 and the sum of the two known numbers
So, for any problem:
$$
\text{Missing number} = 1000 - (\text{First number} + \text{Second number})
$$
This method helps visualize how numbers add up to a total — very useful in mental math and problem-solving!
Let me know if you'd like a visual representation of any of these bars!
Parent Tip: Review the logic above to help your child master the concept of addition worksheet up to 1000.
