In this worksheet, we will learn how to complete a sequence by filling in the gaps.

__Example 1__

Complete the sequence by filling in the gaps:

1 | A | 15 | 22 | 29 | B |

**Answer**

Look for clues.

Here we look at 15, 22 and 29 and notice that 22 - 15 = 7 and 29 - 22 = 7, so the gap is 7.

The sequence consists of numbers that increase by **7**.

**A** = 1 + 7 = **8**

**B** = 29 + 7 = **36**

1 | 8 | 15 | 22 | 29 | 36 |

**Example 2**

Complete the sequence by filling in the gaps:

A | 30 | B | 54 | C | 78 |

**Answer**

This is harder.

54 - 30 = 24

78 - 54 = 24 also.

The gap will be half this, i.e. 12.

**A** = 30 - 12 = **18**

**B** = 30 + 12 = **42**

**C** = 54 + 12 = **66**

18 | 30 | 42 | 54 | 66 | 78 |