1. Writing Expressions

2. Expressions vs. Equations
Expressions use numbers, number symbols and letters (variables) to explain a sentence.
Equations are like expressions except they have an equal sign.

3. examples twelve divided by three Twenty increased by eleven
12 ÷ 3
Twenty increased by eleven
Thirty-seven minus a number
37 - n

4. Real life problem
Joey mows lawns to make some extra money. He charges $21 for each lawn and an extra $2 per hour. Which expression should he use to find out how much to charge his customers?
[A] h
[B] ·h
[C]
[D] 21 – 2·h

5. Translating words into symbols
Addition
Subtraction
Multiplication
Division
Sum
Difference
Product
Quotient
Increase
Decrease
Factors
Equally shared
More than
Less than
Times
Divided by
Plus
Minus
Multiplied by
Added to of

6. Example problems Twelve pieces of candy equally shared by four friends
12 ÷ 4
The product of seven and four
7 x 4
The difference of Twenty and sixteen
20 – 16
y less than 18 times 6
18 • 6 – y

7. Example problems Seven decreased by five The product of four and nine
7 – 5
The product of four and nine
4 x 9
The sum of a number and ten
m + 10
Eight more than a number c
c + 8

8. Example problems The quotient of twenty and two Five minus a number x
20 ÷ 2
Five minus a number x
5 – x
Five less than a number x
x – 5
Eighteen equally shared by six
18 ÷ 6

9. Example problems Three times the sum of a number and 5
3 x (n + 5)
The quotient of m and 2 plus 7.
(m ÷ 2) + 7
four times the quantity of x minus 8
4 x (x – 8)
Eight more than the product of a number and 9
c + 8