This lesson is an extension to a lesson on “Addition Strip Board” where a child uses a traditional Montessori material: Addition Strip Board (buy here). Once the child is comfortable with adding numbers using the board and has a strong understanding of quantity to the numeral concept, this is a great way to introduce a child to combining numbers to make new numbers.

In this video, Adrian is making 10’s.

To combine numbers making 10’s, a child would start at the top (show your child how to bring the strips right to the line). A child would position the blue strip on the left, and then count the squares to see what number is needed to make a ten. A child would then pick the corresponding red strip. 9+1=10; 8 +2 =10; 7 + 3=10 etc.

Here, Adrian was making 10’s, but a child can “make” any number, and the bigger the number is, the more combinations there will be available. For example, number ten yields the largest number conditions.

As always, a child would put the material back on the shelf. The best way to put strips back in a box is to start with the longest strip because there is only one way all the strips will fit into the box.