Who invented brushing your teeth? Thousands of years ago, Babylonians and Egyptians used “chew sticks,” scraping their teeth with tree twigs. Then about 1,400 years ago the Chinese made a brush out of pig hairs in a bamboo handle, while Europeans tried horse hair. Meanwhile, the Egyptians were also rubbing their teeth with a mix of rock salt, mint, ground up flowers, and pepper. The Romans mixed in crushed seashells and bones. Brushing our teeth tastes and feels better than in the old days!
Wee ones: If your toothpaste mixes salt, seashells, soot, bones and mint, how many ingredients in your tasty paste?
Little kids: If you brush your teeth every night starting Sunday but forget to brush on the 5th night, which night do you skip? Bonus: If you brush twice a day, how many times do you brush in 1 full week?
Big kids: If you scrub your brush once tonight, 3 times the next night, 7 times the next, and 15 times the next, what number of scrubs do you brush the night after that to continue the pattern? Bonus: You buy a pack of mega-toothbrushes for your pet shark with 80 bristles in each tuft. How many bristles are there in brushes with 3, 4, 5, and 6 tufts? Count up by 80s!
Answers:
Wee ones: 5 ingredients.
Little kids: Thursday. Bonus: 14 times, since a week has 7 days.
Big kids: 31 times, since you keep doubling the number you add: you add 2, 4, 8…then 16. Bonus: 240, 320, 400 and 480 bristles!
