This chapter looks at the development of number lines, from those with no numbers to those with numbers. Writing numbers on a number line makes it easy to tell which numbers are bigger or smaller. Numbers on the left are smaller than numbers on the right. This remains true when working in only positive or in positive and negative numbers. A number line is a continuous line representing numbers. It is a visual image which will help children to understand our number system. It can be used from the Foundation Stage upwards, and can help to teach addition and subtraction, counting in regular steps, and seeing the pattern of multiplication and division, as well as reinforcing ordinal and cardinal numbers. Children follow instructions involving several ideas or actions. Mathematics involves providing children with opportunities to develop and improve their skills in counting, understanding and using numbers, and calculating simple addition and subtraction problems.