Grade 3 Bar Models: Comparison Bar Models

Worked examples

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

1. Example 1

   Jack has 22 cards. Emma has 18 cards. How many more cards does Jack have than Emma?

   1. Draw two bars: Jack's bar is 22 and Emma's bar is 18. Line them up — the extra piece on Jack's longer bar is the difference.
   2. To find the difference, subtract the shorter bar from the longer bar. 22 − 18: take away the tens, then the ones. 22 − 10 = 12, then 12 − 8 = 4.
   3. Jack has 4 more cards than Emma.

   Answer: 4

2. Example 2

   Sam has 25 pencils. Tom has 12 more than Sam. How many does Tom have?

   1. Draw Sam's bar for 25. Tom has 12 more, so Tom's bar is the same length plus an extra piece of 12.
   2. Add the extra piece to Sam's amount. 25 + 12: add the tens, then the ones. 25 + 10 = 35, then 35 + 2 = 37.
   3. Tom has 37 pencils.

   Answer: 37

3. Example 3

   Sam has 19 pencils. Jack has 16 pencils. How many more pencils does Sam have than Jack?

   1. Draw two bars: Sam's bar is 19 and Jack's bar is 16. Line them up — the extra piece on Sam's longer bar is the difference.
   2. To find the difference, subtract the shorter bar from the longer bar. 19 − 16: take away the tens, then the ones. 19 − 10 = 9, then 9 − 6 = 3.
   3. Sam has 3 more pencils than Jack.

   Answer: 3