Number Models

In September there were 21 students in Jean's class. 2 students moved away in October. In November, 3 new students joined the class. Which number model could be used to find s, the number of students in Jean's class?

• (21 + 2) + 3 = s

• 21 - (2 + 3) = s

• (21 - 2) + 3 = s

• 21 + ( 2 - 3) = s

A number model uses a letter in the place of a number.

• True

• False

Kathleen has $12. She spends $2 on popcorn. How much does she have left? Choose the correct expression.

• 12 + 2

• 12 - 2

• 12 x 2

• 12 / 2

What mixed number does the model represent?

• 3 5/6

• 2 4/6

• 2 2/6

• 1 4/6

What improper fraction does the model represent?

• 23/8

• 23/24

• 21/7

• 22/8

What improper fraction does the model represent?

• 16/18

• 6/16

• 16/6

• 4/18

What improper fraction does the model represent?

• 21/24

• 21/6

• 6/20

• 18/6

What mixed number does the model represent?

• 3 3/6

• 4 3/6

• 1 4/6

• 3 6/3

What mixed number does the model represent?

• 2 6/8

• 2 4/8

• 1 5/8

• 1 4/8

What mixed number does the model represent?

• 3 6/8

• 2 1/8

• 2 7/8

• 1 2/8