Question

Of Alberto’s total number of coins, 168 are quarters. Describe two strategies you can use to find how many coins are not quarters. Estimate the difference. Then choose one strategy and solve.

Answer 1

One strategy is to subtract 168 from the amount you never told us. Or you can keep adding to 168 until you reach the desired amount. The answer is X-168 where X=total amount of coins that you never told us about.

Answer 2

Let the total number of coins is x,

∵ Out of total coins 168 are quarters,

Thus, the coins which are not quarters = total coins - coins which are

quarters

= x - 168,

Alternative method :

We can find the coins which are not quarters by adding any number to 168,

If the number after adding 168 gives the total number of coins,

Then that number would be the answer.