15.5 Algebraic proof — Practise with help

1. $2n$, where $n$ is a whole number.
2. $5n$.

If an answer differs, revisit Section 8.1 for algebraic notation and Section 8.2 for collecting like terms.

Represent the integers as $n$ and $n+1$.

Their sum is $n+(n+1)$. Collect the terms.

$n+(n+1)=2n+1$. This is odd because it is twice an integer plus one.