Three boxes contain 3, 7 and 10 pencils. What is the range of the number of pencils?

الشرح

The largest count is 10 and the smallest is 3, so the range is 10 - 3 = 7 pencils. Answering 10 pencils reports the largest count on its own, but a range measures the distance between the two extremes rather than naming one of them.