7th Grade - Topic 5 Review

A term that contains only a number is a ______.

• constant

• function

• expression

• variable

Answer explanation

A term that contains only a number is called a constant. Unlike variables, which can change, constants have a fixed value.

The number part of a term that contains a variable is a ______.

• variable

• coefficient

• constant

• term

Answer explanation

The number part of a term that contains a variable is called a coefficient. It quantifies the variable, while the variable itself represents an unknown value. Constants are fixed values, and terms are the complete expressions.

A ______ is a letter that represents an unknown value.

• constant

• expression

• equation

• variable

Answer explanation

A variable is a letter that represents an unknown value in mathematics. Unlike constants, which have fixed values, variables can change and are used to express general relationships.

Haddie makes and sells knit scarves. Next week she will pay a $25 fee for the use of a booth at a craft fair. She will charge $12 for each scarf she sells at the fair. Write an expression to determine Haddie’s profit for selling s scarves after paying the fee for the use of the booth.

• 12s + 25

• 12s - 25

• 12s - 50

• 25s - 12

Answer explanation

Haddie's profit is calculated by taking the total revenue from selling scarves, which is 12s, and subtracting the booth fee of $25. Thus, the expression for her profit is 12s - 25.

The cost to buy p pounds of potatoes at $0.32 per pound and n pounds of onions at $0.48 per pound can be determined by using the expression 0.32p + 0.48n. How much will it cost to buy 4.5 pounds of potatoes and 2.5 pounds of onions?

• $2.64

• $2.00

• $1.80

• $3.20

Answer explanation

To find the total cost, calculate 0.32 * 4.5 + 0.48 * 2.5. This equals 1.44 + 1.20 = 2.64. Therefore, the cost to buy 4.5 pounds of potatoes and 2.5 pounds of onions is $2.64.

Simplify the expression.

-8w + (-4z) + 2 + 6w + 9z - 7

• -2w + 5z - 5

• -6w + 5z - 9

• -2w + 3z - 3

• -8w + 5z + 2

Answer explanation

Combine like terms: -8w + 6w = -2w, -4z + 9z = 5z, and 2 - 7 = -5. Thus, the simplified expression is -2w + 5z - 5, which matches the correct answer choice.

Simplify the expression.

-6 + (-2d) + (-4d) + 3d

• -2d - 6

• 3d - 6

• -3d - 4

• -3d - 6

Answer explanation

Combine like terms: -6 + 3d + (-2d) + (-4d) = -6 + (3d - 2d - 4d) = -6 - 3d. Thus, the simplified expression is -3d - 6, which matches the correct answer.

Expand the expression.

3.5(−3n + 4)

• 3.5n - 14

• −10.5n + 14

• 10.5n - 14

• -3.5n + 4

Answer explanation

To expand 3.5(−3n + 4), distribute 3.5: 3.5 * -3n = -10.5n and 3.5 * 4 = 14. Thus, the expression becomes −10.5n + 14, which matches the correct answer.