Grade 4 Bar Models: Unit Review

Worked examples

Real problems from the practice worksheets, solved one step at a time.

1. Example 1

   Lisa has 72 books. 5/12 of them are red. How many books are red?

   1. Draw a bar for all 72 books and cut it into 12 equal units. Each unit is 1/12 of the books.
   2. 1 unit = 72 ÷ 12. 72 ÷ 12 = 6, because 12 × 6 = 72.
   3. 5/12 is 5 units: 5 × 6 = 30.
   4. 30 books are red.

   Answer: 30

2. Example 2

   Emma has 6 cards. 1/2 of them are red. How many cards are red?

   1. Draw a bar for all 6 cards and cut it into 2 equal units. Each unit is 1/2 of the cards.
   2. 1 unit = 6 ÷ 2. 6 ÷ 2 = 3, because 2 × 3 = 6.
   3. 3 cards are red.

   Answer: 3

3. Example 3

   Emma has 5 bags of pencils. Each bag has 59 pencils. How many pencils does Emma have in all?

   1. Draw a bar of 5 equal units, one for each bag, each worth 59.
   2. 5 equal groups of 59 make the whole, so multiply. 5 × 59 = 50 × 5 + 9 × 5 = 250 + 45 = 295.
   3. Emma has 295 pencils in all.

   Answer: 295