Grade 2 Bar Models: Comparison Bar Models

Worked examples

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

1. Example 1

   Amy has 17 marbles. Sam has 11 marbles. How many more marbles does Amy have than Sam?

   1. Draw two bars: Amy's bar is 17 and Sam's bar is 11. Line them up — the extra piece on Amy's longer bar is the difference.
   2. To find the difference, subtract the shorter bar from the longer bar. 17 − 11: take away the tens, then the ones. 17 − 10 = 7, then 7 − 1 = 6.
   3. Amy has 6 more marbles than Sam.

   Answer: 6

2. Example 2

   Mia has 8 books. Amy has 7 more than Mia. How many does Amy have?

   1. Draw Mia's bar for 8. Amy has 7 more, so Amy's bar is the same length plus an extra piece of 7.
   2. Add the extra piece to Mia's amount. 8 + 7 = 15.
   3. Amy has 15 books.

   Answer: 15

3. Example 3

   Max has 20 cookies. Emma has 12 cookies. How many more cookies does Max have than Emma?

   1. Draw two bars: Max's bar is 20 and Emma's bar is 12. Line them up — the extra piece on Max's longer bar is the difference.
   2. To find the difference, subtract the shorter bar from the longer bar. 20 − 12: take away the tens, then the ones. 20 − 10 = 10, then 10 − 2 = 8.
   3. Max has 8 more cookies than Emma.

   Answer: 8