Order of Operations. Mathematics 1st E.S.O.

Teacher: Miguel Ángel Hernández Lorenzo.

ORDER OF OPERATIONS

Example: Mr. Sanchez gave his class the problem 43×5 . Simone got the answer 35, but Joey got 19. Who is right? Explain your answer. Solution: Simone did the addition first: 43×5=7×5=35 . Joey did the multiplication first: 43×5=415=19 . Joey is right, because multiplication should be done before addition.

There is a set of rules to make sure everyone gets the same answer for the same problem. First, do all the work within parentheses. Second, evaluate any exponents. Third, multiply and divide in order from left to right. Fourth, add and substract, in order form left to right.

1. Wendell needed to evaluate the expresion 52−3×8×2 . a. Circle the operation below that must be done first. Addition

Substraction

Multiplication

Division

Exponents

b. Wendell said that the first needed to find the product of 8 and 2. Is Wendell's statement correct? Explain your answer.

2. Using the rules for the order of operations evaluate each of the following expressions. a. 5×36÷3−7 b. 524÷6−8 c. 34×5−6 d. 30÷5×6

3. Jose works for \$9 an hour and gets paid every three weeks. The first week he worked 7 hours, the second week he worked 9 hours, and the third week he worked 10 hours. a. Write an expression to show how much Jose's paycheck will be. b. Evaluate your expression.

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Order of Operations. Mathematics 1st E.S.O.

Teacher: Miguel Ángel Hernández Lorenzo.

4. Evette sells magazine subscriptions. Today, she has sold 18 subscriptions for \$12 each and 13 subscriptions for \$15 each. Write an expression to show how much money Evette has made today. Evaluate this expression.

5. Denny read a new novel. When he started the book, he read 15 pages a day for 8 days. After that, he read 10 pages a day for a further 7 days until he had finished the novel. Write and evaluate an expression to find the number of pages in the novel.

6. Using the rules for the order of operations, evaluate each of the following expressions. a. 324÷62−8 b. 10−4−325 c. 15÷523×22−2×15

7. Mr. Smith goes to the grocery store with a \$20 bill. He buys seven apples at \$0.25 each, five pints of milk at \$0.75 each, and two heads of lettuce at \$1.25 each. a. Write an expression for the amount of change that Mr. Smith will receive. b. Evaluate your expression.

8. Evaluate each of the following expressions. a. 12−5−335 b. 7−43−2×32422 c. 632−234 2

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Order of operations

1º ESO matemáticas en inglés