What is it made of?
Hundreds, tens, and ones, of course!
4 hundreds, 6 tens, and 3 ones, of course!
True. But is that the only answer?
This is the question that we pondered this week in math. Students worked in groups to show 463 using a different amount of hundreds, tens, and ones.
In the picture below, you will see the different group's solutions. How can we be precise? I asked. Precision was our "habit of the week" last week (blog post coming soon), so we thought about ways we could double-check that our new representation still added up to 463. We decided that the surest way would be to use the paper/pencil addition method to add up the hundreds, tens, and ones. This allowed us to practice a new mental math strategy: add a 0 to the amount of tens you have to figure out what number they represent! For example, 17 tens equals 170! You can see in the left column that we tried using 15 for the value of the tens, and we didn't get the correct answer. We needed to put 150!
Decomposing numbers in this way builds flexibility in the students' minds, which is important when trying to understand how numbers work, exploring relationships between them, and refining our mental math strategies.
As we know, it takes practice to build flexibility. We practiced our mental flexibility by playing a mathy version of the classic card game War. In this version, each card has a description of a number on it.
Each player flipped over their top card, then used our addition strategy to figure out what number it represented.
Just like in the classic game, whoever had the higher number won that round.
You've seen homework this week with similar number riddles. If your child found them difficult to solve, don't be afraid to make up some of your own and practice adding them up! Just choose a certain amount of hundreds, tens, and ones, and make sure that at least one of those numbers is greater than 9.
Little people, big minds.