Home » Math » Practice the “Mentally Add 100” Skill with this FREE Game

Mentally add 100 has children spin and cover up the answer. This game is a great way for children to add 100 to numbers in the hundreds and thousands.


It’s day three of our six days of Christmas tree printables. It has been fun coming up with different activities that focus on math skills and Christmas trees!

And today we have a no-prep adding by 100 games.

Before the Activity:

You know me… right? You know that as much as I love fun games, these should only be done after hands-on learning. And this learning should be helping our children develop number sense and being able to visualize math concepts.

In my class, 30 Scripted Lessons For Building Number Sense, adding one, ten, and hundred is carefully taught and practiced.

Though there are many ways to practice adding 10 or adding one, adding 100 is easiest with base ten blocks.

In a quick lesson, have children build different numbers with base ten blocks. Make sure they are building all sorts of numbers, like numbers in the ones, tens, hundreds, and even thousands.

Next, have the child add a flat or 100 to the pile and figure out what they have now.

Let’s say they built the number 13. They should have one long and three cubes. When they add 100, now they have 1 flat, one long, and three cubes. The answer is 113.

(If you are unsure how to teach this, my scripted lessons will walk you through this step by step.)


This game is easy to prep, and will have your children practicing adding by 100 in no time.

  1. First, print off the game boards and spinners you want to use.
  2. Next, cut out the spinners.
  3. Finally, gather up a pencil and paperclip for the spinner (or get one from Amazon) and blocks to cover up the numbers.

Brybelly 12 Assorted Rainbow 4-inch Arrow Game Spinners in 4 Colors, 3 Arrows Per ColorBrybelly 12 Assorted Rainbow 4-inch Arrow Game Spinners in 4 Colors, 3 Arrows Per ColorBrybelly 12 Assorted Rainbow 4-inch Arrow Game Spinners in 4 Colors, 3 Arrows Per ColorLearning Resources Snap CubesLearning Resources Snap CubesLearning Resources Snap Cubes


Game Time: Mentally Add 100 Game

The game is super easy to play.

  • First, player one spins the spinner made of a pencil and paper clip.
  • Then player one solves the problem, and player two
    checks it on the calculator.
  • If player one answered correctly, he may cover up that
    number on the Christmas tree.
  • Now it is player two’s turn to spin and solve, while player
    one checks the math.
  • Players take turns doing this until someone has covered
    up every number on the tree.

What’s Included

There are three different game boards. The first one has children adding 100 to numbers in the 100’s.

The next one gets a little harder, as they are now adding to numbers in the thousands. And these are not as simple as just moving the number in the hundreds place up one digit. They will see expressions like 3,986 + 100.

Last by not least, our sweet little ones will be adding one, ten and a hundred to numbers.

I hope your kiddos have fun playing this game and get in some extra practice with this extremely important skill.

You’ve Got This,



You may also like:


Practice adding by 10’s and then move to harder numbers using the hundreds chart.