To give experience in the exchanging process, i.e., 10 of one category make 1 of the next higher category. To give practice in changing as a preparation for further exercises.
A tray containing a supply of units, tens, hundreds and thousands.
A dish large enough to hold a supply of units.
Castors, large mat.
4 – 5 years
A small group exercise.
– Units to Tens A good supply of units and tens on a tray and a castor for each child.
Invite the children to help you count the units.
Begin counting the units into a castor – stop when you reach ten.
Remind the children that there are ten units in one ten.
Explain that when you count to 10 you must exchange the 10 units for 1 ten.
When all the exchanges have been made, read the quantity of beads, e.g., seven tens and four units/seventy-four.
– Tens to Hundreds Using the same procedure exchange 10 tens for 1 hundred.
– Hundreds to Thousands Using the same procedure exchange 10 hundreds for 1 thousand.
EXERCISE 1: The child works with the material as shown.
Presentation: At a later date do the reverse process (before starting subtraction).
– Thousands to Hundreds:
A good supply of thousands at a mat.
Remind the children that 10 hundreds are exchanged for a thousand.
Explain that you can reverse this procedure: exchanging 1 thousand for 10 hundred.
Children exchange thousands in a systematic manner.
– Hundreds to Tens:
Using the same procedure exchanging 1 hundred for 10 tens.
– Tens to Units:
Using the same procedure exchanging 1 ten for 10 units.
EXERCISE 2: The child works with the material as shown.
Place a quantity of units, tens, hundreds and thousands all together in a pile on a mat.
Playfully, say to the children, “I wonder how much we have here?” “How can we find out?”
Hopefully the children will suggest sorting the quantity into their hierarchies and then count them beginning with the units and changing when necessary until they have all been counted.
Get the child to use the Large Number Cards to show the quantity in written form.
EXERCISE 3: The child works with the material as shown.