Numbers can be placed in order on a number line like this:

When there are numbers missing, say them in your head as you move along the line.

Example

Which number goes where the ? is?

Answer

Here we say   3... 4... 5... 6... 7, so the 5 is where the ? is.

Don't be put off by the fact that several numbers are missing, just count along until you reach the question mark - that's the one you need.

Let's use your detecting skills and get started on the questions.