# 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.

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
• 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.

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

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

# Playdough ice cream

Following the monkey and alligator song, I suggested the kids use playdough to make monkeys and a log for an alligator.  This proved too challenging for most of them; they were afraid they couldn’t make it look like the animals.  Our Kool-Aid-dyed playdough smelled like synthetic fruit and so kids quickly started making ice cream scoops instead.

I challenged them to make one-five scoops and even taught some of them how to roll a cone, sneaking in some geometry language when we talked about what made it a cone.  Most kids had to be taught how to roll a ball of playdough, making me happy I had brought it.  We compared the ice cream cones of a pair of kids: who had more scoops?  Who had fewer?

Playdough is very easy to make.  Keep some food colouring and cream of tartar at hand; there is absolutely no reason to spend time and money at the additional trip to the toy store to purchase Play-Doh.

Sources:

Playdough recipes at Instructables

Just to show that there is nothing new under the sun:  Girls making Neopolitan ice cream cones and wonderful math play with playdough at Here Come The Girls.

# Counting Songs: Five Little Monkeys Hanging From a Tree

My first visit with the 2-5-year-olds at the daycare set the tone:  We sang a counting-back song (and per request sang it again before I left) and made playdough scoops of ice cream to count up to and down from 5.

I introduced the kids to “Five little monkeys hanging in a tree” to practice counting backwards and for the shock effect of the SNAP of the alligator which engages everybody!  The slightly annoying Mr. Mike has a good presentation of the song here:

More resources:

BBC School Radio – Counting Songs:  Videos, lyrics and music for you to learn the songs before singing with kids.

Songs for Teaching – Number Chants and Counting Songs: Teaching Early Mathematics Skills, Shapes, Money and Telling Time