There are many questions you can explore about your own body and age with mathematics. For example, approximately how many Sunday nights can you expect to sleep until you are 100 years old? Just take 100 years, minus your current age, and multiply that result by 52 (weeks in a year with a Sunday). For example, if you are 25, the answer would be (100 - 25) × 52 = 3,900. How many of those will be good night’s sleep is up to you.

In Pascal’s triangle, each number is equal to the two numbers directly above it.

To calculate the number of times your heart has beaten since you were born, you need the help of a watch or clock. First, time your heartbeats per minute (to find out how to count your pulse, see “Everyday Math”); then multiply beats per minute × 60 minutes (in an hour) × 24 hours (in a day) × 365.25 days (in a year) × your age. For example, 72 heart beats × 60 × 24 × 365.25 × a person who is 30 = 1,136,073,600 beats since the person was born. Of course, this is an approximation, since the heart usually beats slower at night, and it speeds up when you see the bill for your latest car repair.

Figuring out how much air you breathe during a lifetime is another fun mathematical calculation. If you optimistically decide you want to eventually be 100 years old, and the average person inhales about one pint (or 0.47 liters) of air per breath, you can do the math. First take the number of breaths you take while at rest per minute (say about 21 per minute) × 0.47 liters × 60 minutes × 24 hours × 365.25 days × 100 years old = 519,122,520 liters. Again, this is only an approximation.