Subtraction - With Changing

Age
3-6

Materials

 * 1) Unlimited Golden Beads.
 * 2) Large Number Cards.
 * 3) At least 2 sets of Small Number Cards.
 * 4) At least 2 trays and unit pots fro carrying.
 * 5) An operational mat.
 * 6) A floor mat.

Presentation

 * 1) This is a group activity. Directress invites the children to take the Large and Small Number Cards from the shelf and to lay out the cards on the floor mat.
 * 2) Meanwhile, Directress sets up the 'Bank' and lays out the operational mat on the table.
 * 3) The Directress sets a subtraction question, which involves changing, e.g. 3214-1246.
 * 4) Directress gives child a tray and asks her to fetch the large number cards and the corresponding beads for 3214.
 * 5) Child A does that and places the beads on the operational mat with the cards beside it.
 * 6) The Directress then asks Child B to take away the quantity, 1246.
 * 7) The child will realize that he does not have enough units to take away when he tries to take away 6 units from the 4 units on the mat.
 * 8) Then he will be told that he could change one of the Ten Bead Bars on the mat for 10 Golden Beads at the bank.
 * 9) The 10 Golden Beads exchanged are placed together with the rest on the mat.
 * 10) The child then takes away 6 units.
 * 11) The child then tries to take away 4 tens and he will realize that there is none for him to take away.
 * So, he exchange 1 One Hundred Square for 10 Ten Bead Bars.
 * 1) He then takes away 4 tens from the Ten Bead Bars on the mat.
 * 2) The child goes on to try taking away two hundreds from the one hundred left on the mat. He finds that he can't and so he exchanges 1 Thousand Cube for 10 Hundred Squares.
 * 3) From the Hundred Squares on the mat, the child takes away 2 hundred.
 * 4) Finally, the child takes 1 thousand from the 2 thousand left on the mat.
 * 5) The total 1246 taken away are placed on the tray and the corresponding small number cards are also fetched and placed on tray.
 * 6) Child A then starts to count the number of beads left on the mat.
 * 7) He brings the beads down to the bottom of the mat as he counts them as in previous exercises and find the total to be 1968.
 * 8) The corresponding small number cards are fetched and placed beside the beads.

Control Of Error
Directress guided.

Purpose

 * Show the children how to 'change' when doing subtraction.