How Many Are Hidden? Buttons in a Bag
Both pictures have the same number of buttons.
How many buttons are hidden in the bag? How do you know? How can you finish the equation to make it true?
Look at the blue numbers on both sides of the equation. What do you notice? What about the red number?
- Now there are more than 20 buttons. You get to decide how many!
How many might be hidden in each bag? How do you know?
- Finish the equation to make it true.
What do you notice about how the numbers changed this time?