A Common P4 Challenging SA2 Math Concept
Before & After – 1 Unchanged with further cutting of model.
Question: In a basket of pears and apples, there were half as many pears as apples. John added 21 more pears into the basket. As a result, there were 3⁄4 as many pears as apples. Find the number of fruits in the bask in the end.
Apples remain unchanged. Thus we shall make the number of units for apples the same “before” and “after”. This can be done by cutting each unit in the “before” model into two.
You will notice now that after the “cutting”, the number of units for Apples “before” and “After” are both the same i.e. equal to 4 units.
Now if we look at what has changed. Pears has increased from 2 units to 3 units. The increase of 1 unit is attributed to the additional 21 pears. As such –
1 unit = 21
7 units = 7 x 21 = 147
Number of fruits in the basket in the end is 147.