Math in Our World: A Soapy Situation

A young girl washes her hands at a sink. A grown-up helps.

It’s important to wash your hands to keep them clean. Jesse likes to slowly count while she washes her hands. That lets her know that she spent enough time using soap and water.

Sometimes she counts to 20.

Sometimes she counts to 15, and then she counts to 5.

Sometimes she counts to 12, and then she counts to 8.

  1. Use numbers, math words, objects, or pictures to show what is happening.
  2. What do you notice? What do you wonder?
  3. What math questions can you ask about this situation? Answer all the questions that you can!
  • Think about two numbers you can add together to make 20.
  • If you’re stuck, use a number rack. How can you move the beads on the rack to make 20 different ways? If helpful, you can also use the Number Rack app.
  • Think about counting to 10 and then counting 10 more. What happens if you change the first number to 11? What about 12? How does that change the other number you count to?
  • Feeling creative? Try skip-counting! You can count by 2s, 5s, or 10s while you wash your hands. Can you say the first 20 numbers in your skip-counting pattern?
  • Can you come up with a different way to count each time you wash your hands?
  • The next time you wash your hands, show someone how you’re counting. Use numbers and math words to explain your thinking.
  • Ask whether they have any other questions you can answer!

Can you think of other ways to use math while you wash your hands? Think about counting backward or counting by tens. Maybe you know a math song that takes about 20 seconds.