Let's solve the problem step by step.
We are given a grid of numbers with some missing. The goal is to
fill in the missing numbers so that each row and column follows a logical sequence — likely counting in order (i.e., consecutive integers).
Here is the image layout:
```
1 __ 3 __ 5
__ __ 8 __ 10
11 __ __ __ 15
__ 17 18 __ 20
```
We will go row by row and fill in the blanks, assuming the numbers increase by 1 sequentially across each row and down each column.
---
Row 1:
`1 __ 3 __ 5`
We know:
- 1 → next number should be 2 → then 3 → then 4 → then 5
So the missing numbers are:
- Between 1 and 3 →
2
- Between 3 and 5 →
4
✔ Row 1: `1 2 3 4 5`
---
Row 2:
`__ __ 8 __ 10`
We know:
- Numbers should be increasing.
- We have 8 and 10, so the pattern is likely:
- First number: ?
- Second number: ?
- Third: 8
- Fourth: ?
- Fifth: 10
If we assume it's counting up by 1s, then:
- Before 8: 6 and 7
- After 8: 9
- Then 10
So:
- First blank:
6
- Second blank:
7
- Fourth blank:
9
✔ Row 2: `6 7 8 9 10`
---
Row 3:
`11 __ __ __ 15`
We know:
- Starts at 11, ends at 15
- So: 11, 12, 13, 14, 15
Missing numbers:
- After 11 →
12
- Then
13
- Then
14
✔ Row 3: `11 12 13 14 15`
---
Row 4:
`__ 17 18 __ 20`
We know:
- 17 and 18 are consecutive
- Then comes 20
- So before 17: must be 16
- After 18: must be 19
So:
- First blank:
16
- Fourth blank:
19
✔ Row 4: `16 17 18 19 20`
---
Now let’s verify the columns to make sure they’re consistent.
Check Columns:
Column 1:
1, 6, 11, 16 → increases by 5 each time?
1 → 6 (+5), 6 → 11 (+5), 11 → 16 (+5)
✔
Column 2:
2, 7, 12, 17 → +5 each time
✔
Column 3:
3, 8, 13, 18 → +5
✔
Column 4:
4, 9, 14, 19 → +5
✔
Column 5:
5, 10, 15, 20 → +5
✔
Perfect! All rows and columns follow a pattern:
each row increases by 1, and
each column increases by 5.
---
Final Answer:
```
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
```
✔ All missing numbers filled correctly.
---
Summary of Missing Numbers:
- Row 1: 2, 4
- Row 2: 6, 7, 9
- Row 3: 12, 13, 14
- Row 4: 16, 19
So the completed grid is:
```
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
```
Parent Tip: Review the logic above to help your child master the concept of numbers worksheet 1 20.
