How Many Fingers Are There in Houston?

Problem Statement

As of 2023, the population of Houston, Texas was estimated to be 2,314,157 people. If we assume that each person has two hands and each hand has five fingers, how many fingers are there in Houston? The two hands and five fingers for every person is certainly not true in real life, but it gives us a nice order of magnitude answer.

I Need a Hint!

Set up an expression where you take the original number of people in Houston, convert that to the number of hands in Houston, and then convert that to the number of fingers in Houston. This is an example of dimensional analysis.

Solution

We can solve this problem using dimensional analysis. The number of fingers is:

$$(2,314,157people)\left(\frac{2hands}{1person}\right)\left(\frac{5fingers}{1hand}\right)=23,141,570fingers$$