||4 – 6 years approx.
The trays are set aside and the children gather around the mat.
The Montessori Directress then tells the children that,“We are going to add the numbers on the mat, starting with the units.”
One child brings down the units from the top of the table, places them all together, and counts them.
On reaching ten units, the Montessori Directress tells the child he can exchange the ten units by putting them into the changing pot and bringing them to the bank.
The ten units are then exchanged for one ten bead bar, which is brought to the mat and placed above the ten bead bars of the first number
The child collects and places the corresponding large number cards below the beads.
The second child brings down all the tens, counts them and places the corresponding number cards below them.
The hundreds are brought down and counted and labelled as before.
When all the beads are counted and all the corresponding quantities in number cards have been placed below them, the cards are then overlapped.
The large overlapped cards are then placed below the small number cards, which have remained on the right hand side of the mat.
The Montessori Directress then recaps, saying “We started with 236 beads and added 125 and now we have a larger number, 361.
Always restate the sum, pointing out to the children that two numbers were added together to make one large number. This is reflected in the size of the cards and the quantities of the beads.
End the work cycle.