Free Printable Worksheets for Kids - Missing Number Worksheets 1-20 - Free Printable

Problem Description:

The task is to fill in the blanks in a series of number sequences. Each sequence appears to follow a simple arithmetic pattern, typically involving consecutive numbers or a consistent increment.

Solution Approach:

1. Identify the Pattern: For each row, determine the relationship between the given numbers. Most likely, the numbers are increasing by a constant difference (e.g., +1, +2, etc.).
2. Fill in the Blanks: Use the identified pattern to fill in the missing numbers.
3. Verify: Ensure that the filled-in numbers maintain the consistency of the pattern.

Step-by-Step Solution:

#### Left Column:
1. Row 1: `3 _ 5`
- Pattern: Numbers increase by 1.
- Missing number: `4`
- Filled: `3 4 5`

2. Row 2: `_ 5 6`
- Pattern: Numbers increase by 1.
- Missing number: `4`
- Filled: `4 5 6`

3. Row 3: `8 _ 10`
- Pattern: Numbers increase by 1.
- Missing number: `9`
- Filled: `8 9 10`

4. Row 4: `4 _ 6`
- Pattern: Numbers increase by 1.
- Missing number: `5`
- Filled: `4 5 6`

5. Row 5: `6 7 _`
- Pattern: Numbers increase by 1.
- Missing number: `8`
- Filled: `6 7 8`

6. Row 6: `_ 2 3`
- Pattern: Numbers increase by 1.
- Missing number: `1`
- Filled: `1 2 3`

7. Row 7: `7 8 _`
- Pattern: Numbers increase by 1.
- Missing number: `9`
- Filled: `7 8 9`

8. Row 8: `3 4 _`
- Pattern: Numbers increase by 1.
- Missing number: `5`
- Filled: `3 4 5`

9. Row 9: `_ 6 7`
- Pattern: Numbers increase by 1.
- Missing number: `5`
- Filled: `5 6 7`

10. Row 10: `_ 3 4`
- Pattern: Numbers increase by 1.
- Missing number: `2`
- Filled: `2 3 4`

#### Right Column:
1. Row 1: `12 _ 14`
- Pattern: Numbers increase by 1.
- Missing number: `13`
- Filled: `12 13 14`

2. Row 2: `17 18 _`
- Pattern: Numbers increase by 1.
- Missing number: `19`
- Filled: `17 18 19`

3. Row 3: `13 _ 15`
- Pattern: Numbers increase by 1.
- Missing number: `14`
- Filled: `13 14 15`

4. Row 4: `15 16 _`
- Pattern: Numbers increase by 1.
- Missing number: `17`
- Filled: `15 16 17`

5. Row 5: `9 _ 11`
- Pattern: Numbers increase by 1.
- Missing number: `10`
- Filled: `9 10 11`

6. Row 6: `_ 12 13`
- Pattern: Numbers increase by 1.
- Missing number: `11`
- Filled: `11 12 13`

7. Row 7: `_ 19 20`
- Pattern: Numbers increase by 1.
- Missing number: `18`
- Filled: `18 19 20`

8. Row 8: `14 _ 16`
- Pattern: Numbers increase by 1.
- Missing number: `15`
- Filled: `14 15 16`

9. Row 9: `_ 17 18`
- Pattern: Numbers increase by 1.
- Missing number: `16`
- Filled: `16 17 18`

10. Row 10: `10 11 _`
- Pattern: Numbers increase by 1.
- Missing number: `12`
- Filled: `10 11 12`

Final Answer:

```
Left Column:
3 4 5
4 5 6
8 9 10
4 5 6
6 7 8
1 2 3
7 8 9
3 4 5
5 6 7
2 3 4

Right Column:
12 13 14
17 18 19
13 14 15
15 16 17
9 10 11
11 12 13
18 19 20
14 15 16
16 17 18
10 11 12
```

Thus, the completed worksheet is:
\boxed{
\begin{array}{ccc|ccc}
3 & 4 & 5 & 12 & 13 & 14 \\
4 & 5 & 6 & 17 & 18 & 19 \\
8 & 9 & 10 & 13 & 14 & 15 \\
4 & 5 & 6 & 15 & 16 & 17 \\
6 & 7 & 8 & 9 & 10 & 11 \\
1 & 2 & 3 & 11 & 12 & 13 \\
7 & 8 & 9 & 18 & 19 & 20 \\
3 & 4 & 5 & 14 & 15 & 16 \\
5 & 6 & 7 & 16 & 17 & 18 \\
2 & 3 & 4 & 10 & 11 & 12 \\
\end{array}
}