Adam and Bryan have 90 marbles.
Adam has 20 less marbles than Bryan.
Find the number of marbles that Bryan has.
- Which model should we draw?
(1) Model Part-whole
(2) Model Comparison
- Is the total given?
(1) Yes
(2) No
- Who gets the shorter bar?
(1) Adam
(2) Bryan
- Number of marbles that Bryan has =
(a)
Which model should we draw?
(1) Model Part-whole
(2) Model Comparison
We should draw a (2) Model Comparison.
(b)
Is the total given?
(1) Yes
(2) No
(1) The total is given.
(c)
Who gets the shorter bar?
(1) Adam
(2) Bryan
Adam has 20 less marbles than Bryan.
So, Adam (1) gets the shorter bar.
(d)
If 20 more marbles are given to Adam, Adam and Bryan will have the same number of marbles.
Number of marbles that Bryan has
= (90 + 20) ÷ 2
= 110 ÷ 2
= 55
Answer(s): (a) 2; (b) 1; (c) 1; (d) 55