Variable Expressions and Open Sentences

A(n) _______________ represents an unknown quantity or number

• Expression

• Factor

• Variable

• Equation

Which mathematical expression represents "eight times a number"

• 8/r

• 8r

• r - 8

• 8 + 2r

Which of the following does not show "a number times 3"

• m x 3

• m = 3

• 3m

• m * 3

Which problem statement could be represented by this number sentence? 12 + 36 = c

• Amy made 12 cupcakes. Maya made 36 cupcakes. They divided their cupcakes evenly. How many cupcakes did they each receive?

• Amy made 12 cupcakes. Maya made 36 cupcakes. How many more cupcakes did Maya make?

• Amy made 12 cupcakes. Maya made 36 more cupcakes than Amy. How many cupcakes did Maya make?

Which of the following equations does not contain a variable?

• 87 - 4 x (m + 3) = 37

• 7r + 1 = 22

• (l + w) + 8 = 39

• 39 - 2 + (9 x 2) = 55

If G represents a number, which of these means the same as the expression G - 10

• Ten more than a number

• Ten divided by a number

• Ten times a number

• Ten less than a number

Which can be solved using the open sentence 21 x 5 = p?

• Bailey gave each of his twenty-one classmates 5 pieces of chocolate. How many pieces of chocolate did Bailey give to his classmates?

• Twenty-one students went to the Fall Festival. Five others joined them later. How many students were at the festival altogether?

• Marty collected twenty-one cans of cat food and Peter collected five. How many more cans of cat food did Marty collect than Peter?

• Twenty-one students were put into five groups. How many students were put into each group?

Which expression goes with the phrase: "a number less than 9"?

• 9/n

• 9 - n

• n - 9

• 9 + n

Lisa needs $18 more in order to buy a winter jacket that costs $65. Which open sentence can be used to find j, the amount of money Lisa has already saved?

• j = 65 + 18

• 18 x j = 65

• j + 18 = 65

• 65 + j = 18

Teresa baked 4 trays of cookies with 12 cookies on each tray. How many cookies did Teresa make?

• 4 x 12 = c

• c x 12 = 4

• 4 x c = 12

• 4 + 12 = c