When you do a simple thing like flicking a light switch, your brain is moving a LOT of different parts. Your hand is a crazy collection of bones, which are hard like sticks, and muscles, which are long strings that push and pull the bones. Turns out there are 17 little muscles in the palm of your hand, and 18 more muscles in your forearm that move your fingers. Try to get a grip on that!
Lace up: Can you find 3 things smaller than your hand?
Jog: There are 18 muscles in your forearm and 17 in your hand. How many more muscles are in your forearm?
Sprint: There are 18 muscles in your forearm. How many fewer muscles than 20 is that?
Hurdle: There are 18 muscles in your forearm and 17 in your hand. If you add up the muscles in both hands and both forearms, how many muscles is that?
High Jump: Not everyone agrees on what counts as a muscle: some people say there are 650 muscles, while others say it’s 840. What’s the difference between those two numbers?
Answers:
Lace up: We bet you can! Items could include small toys, erasers, paperclips, crayons…
Jog: 1 more muscle in your forearm.
Sprint: 2 fewer, because 20 – 18 = 2.
Hurdle: 70 muscles, because there are 17 + 18 = 35 muscles on each side, and 35 + 35 = 70.
High Jump: 190 muscles. You can either subtract by regrouping (840 – 650 = 700 – 600 + 140 – 50 = 100 + 90 = 190) or you can add up from 650 (50 brings you to 700, 100 brings you to 800, 40 brings you to 840; 50 + 100 + 40 = 190).
