The Gauss family has three boys aged $7,$ a girl aged $14,$ and a boy aged $15.$ What is the mean (average) of the ages of the children?
To find the mean, I need to add up all the ages and divide by the number of children. So the sum of the ages is $7 + 7 + 7 + 14 + 15 = 50.$ And the number of children is $5.$ So the mean is $50 \div 5 = 10.$ 