Reasoning is fundamental to knowing and doing mathematics.

Reasoning enables students to make use of all their other mathematical skills and so reasoning could be thought of as the glue

which helps mathematics makes sense.

Again, reason mathematically by following a line of enquiry, conjecturing relationships and generalisations, and developing an argument,

justification or proof using mathematical language.

When faced with a mathematical challenge, reasoning helps us to make use of relevant prior knowledge

such as how to tackle this type of problem or a particular calculation method that could prove useful.

The reasoning involved is complex and unique to the individual, as each of us has a different mix of past mathematical experiences.