Let’s Learn Mathematics (Primary Level) — Model Method 4

Continuation from Let’s Learn Mathematics (Primary Level) — Model Method 3

Here is another example on comparison model to compare two or more items.

Question: 8 similar dictionaries and 12 similar assessment books cost S$196. Each assessment book costs S$2 less than each dictionary. How much does each dictionary cost?

First, draw the model based on the question.

Comparison model based on the question

Each assessment book costs S$2 less than each dictionary, thus 8 similar dictionaries cost S$16 more than 12 similar assessment books.

S$2 x 8 = S$16

From the model, we can see that the total cost is 8 units of dictionaries, 12 units of assessment books and S$16. To find the cost of a single unit, we subtract S$16 from the total cost.

S$196 − S$ 16 = S$180

Total units = 8 + 12

= 20 units

S$180 ÷ 20 = S$9

The cost of a single unit is S$9. The question asks for the cost of each dictionary, thus we need to add S$2 to get the final answer.

S$9 + S$2 = S$11

Each dictionary costs S$11.

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Disclaimer: The Mathematics questions are purely created for discussion purpose. Any resemblance to actual questions from books or schools is coincidental.