6.EE.B.6: Use variables to represent numbers and write expressions — Practice

Concepts

A rope of unknown length is cut into two pieces. One piece is 3
feet long, and the other piece is $r$ feet long. The two pieces
together were 15 feet before cutting. Is $r$ here an unknown
number or a ranging number?

Ranging — $r$ could be any number depending on how the rope happens to be cut.

Unknown — $r$ stands for one specific value that makes $r + 3 = 15$ true.

Unknown — but only because the problem uses the word "unknown number."

Ranging — because the total length, 15, is also unknown.

A parking garage charges $\text{\char"0024}2$ per hour. Write an expression for
the total cost of parking for $h$ hours, where $h$ could be any
amount of time a customer parks. Is $h$ here an unknown number or
a ranging number?

Ranging — $h$ represents any number of hours a customer might park, not one specific value.

Unknown — $h$ stands for exactly one specific number of hours that we need to solve for.

Ranging — but only because the cost per hour, $2, changes.

Unknown — because every customer parks a different, definite number of hours.

A problem asks you to write an expression for the cost of buying
$b$ books at $8 each. Before writing $8b$ , a student is supposed
to state what the variable means. Does writing "Let $b$ = the
number of books purchased" before the expression follow the
"define the variable" step from the lesson? Enter 1 for yes or 0
for no.

Procedures

Write an expression for "9 more than a number $k$ ." If your
expression is $k + 9$ , enter 9. If it is some other form, enter
the number you would add to $k$ .

Which expression correctly represents "6 less than a number $w$ "?

$6 - w$

$w + 6$

$w - 6$

$6w$

Write an expression for "a number $z$ divided by 5." Evaluate
your expression at $z = 20$ . Enter the numerical value.

Which expression correctly represents "8 less than three times a
number $m$ "?

$8 - 3m$

$3(m - 8)$

$3m + 8$

$3m - 8$

6.EE.B.6 Tutor Intake -- Variables and Expression Writing

Concepts

Procedures