Understanding terms and expressions

In algebra, letters are used when numbers are not known.

Algebraic terms, like 2s or 8y, leave the multiplication signs out. So rather than 2 \times s, write 2s, and rather than 8 \times y write 8y.

A string of numbers and letters joined together by mathematical operations such as + and - is called an algebraic expression, for example r + 2s


Suppose that {g} is the cost of child admission and {k} is the cost of adult admission to the zoo:

a) How much does it cost for the Khan family of {3} children and {3} adults to visit the zoo?

b) Write an algebraic expression for the cost for the Norman family of {5} children and {4} adults to visit the zoo.

a) Cost for {3} children = 3g

Cost for {3} adults = 3k

Total cost = 3g + 3k

b) 5g + 4k