Goal: The learner will write variable expressions and equations. Lesson 12.1

Key Phrases These words signal what operation needs to be preformed. Addition Subtraction Multiplication Division Plus Minus Times Divided by The sum of The difference of The product of The quotient of Total Decreased by Multiplied by Separate into equal parts Added to Less than Of More than Subtracted from twice These words signal what operation needs to be preformed.

Write the phrase as a variable expression 3 pieces added to x pieces in the art show The sum of 4 and a number n The difference of 12 and a number x 9 fewer than the number of boys b

A Few For You 16 decreased by a number d The total of 10 and a number n A number h increased by 15

Try It Again. The product of 5 and the number of girls, g 8 multiplied by a number, x The quotient of a number, h, and 6 24 divided by the number of hours, h

What if… Sometimes they don’t give a specific variable to use. Pick a variable that makes sense. Try not to use O, T, or S 25 divided by the number of inches Twice the number of people

Writing Equations “equals” and “is” represent “=“ A number x minus 5 equals 12. 15 times a number y is 75.

You Try It A number n added to 4 is 11. The quotient of x and 96 is 8.

Model a Situation Today’s high temperature of 59˚F is 3˚F less than yesterday’s high temperature t. Write a subtraction equation you can use to find t.

Model a Situation Three friends share the cost of a dinner equally. The total cost of the dinner is $27. Write a multiplication equation that you could use to find the amount a that each friend pays.

Assignment P.631 #3-17, 29-32 Challenge 24-25