Counting, Addition and Subtraction Machine

What happens in addition and subtraction?  Using a machine (only force used is gravity and little fingers) can illustrate this process.

There are many good reasons to use number bonds when working with addition.  (I include some resources below.)  My goal with this activity was to make a machine that can add as well as subtract so I can have a fun manipulative for addition while the older kids can explore number bonds.  Also, I have a few idea for small-world role play involving the machine…

The fabulous The Imagination Tree has an addition machine, which I expanded to show the inverse relationship between addition and subtraction.

Several skills can be built on here: using numerals, counting using 1:1 correspondence, combining groups of objects to work out addition problems, recognising small amounts and – if you add objects with different shapes or colors – grouping.

I am a hoarder of tend to collect cardboard and paper and so had plenty of material to build the machine.  See the process below.  The machine was tested by our resident Kindergartener and Toddler before taken to sea in the daycare group.

Addition and subtraction machine - Daycare Math

Building the addition and subtraction machine using one box, three tubes and masking tape.  Two tubes for the addends on top go down to the sum tray. One tube for the subtrahend leads in from the tray, leaving the difference.

Materials:

  • Cardboard mailing box, appr. the size of a shoe box
  • Cardboard tubes from paper towel rolls and wrapping paper
  • Masking tape
  • Tool: utility knife
  • Decoration: acrylic paint and permanent marker (mod podge and paper is a good alternative)
  • Addends/subtrahends: pom-poms – colorful, fun to touch, non-edible and will not harm when tossed.

I tested the machine with the pre-schoolers and only one, the 5-year-old who goes to a school readiness program, was ready to use it.  The 3-4-year-olds did not grasp the concept of addition.  Popping the pompoms into the tubes, however, was fun for all.  A tube will do for that purpose!  We used tongs and a starter version of chop sticks to pick up the pompoms for some added fine motor practice.

Even the 2-year-old was using the machine but for counting.  A tray is useful.

Even the 2-year-old was using the machine but for counting.  A tray is useful.

Sources:
Addition machine:  Addition and Counting Machine Maths Activity! – The Imagination Tree.

Number bonds: Teaching number bonds – Math Coach’s Corner