Squares are made in a row with matchsticks, as shown. Joined squares share a side. How many matchsticks are needed for Shape 10?

In the expression $4n+7:-\ast \ast n$** is the variable
- **$4n$** is a term — it means $4\times n-\ast \ast 4\ast \ast$ is the coefficient of $n-\ast \ast 7\ast \ast$ is a constant term
- **+** is the operation joining the terms

When a number sits next to a variable with no symbol between them (like $4n$), it always means multiplication. We never write × between a number and its variable.