Writing equations from worded statements Word Expression Operation ‘the sum of’, ‘is added to’, ‘plus’ + ‘the difference between’, ‘is subtracted from’, ‘minus’ - ‘the product of’, ‘is multiplied by’, ‘times’ × ‘the quotient of’, ‘is divided by’ ÷ ‘is equal to’, ‘the result is’, ‘gives’ =

Example One Five times a certain number gives 15. When 12 is subtracted from a certain number, the result is 6. When 4 is added to 12 times a number the answer is 40. When the difference between 8 and a number is divided by 7 the result is 3.

Example Two The cost of hiring a surfboard is $9 plus $3 per hour. If h is the number of hours, write an equation for the hiring cost. If a surfer has $30, how many hours can she hire the board for? If the surfer returns the board undamaged, she gets a rebate of $0.50 per hour. How much money did the surfer from part b) get back?

Example Three The sum of three consecutive numbers is 165. Write an equation for this. What are the three numbers?

Example 4 A swimming pool has a perimeter of 155 metres. If the width is one fourth the length, determine the area of the pool.