## Sunday, 18 May 2014

### Montessori Activity: Subtraction Board (减法[jiǎn fǎ])

AGE: From 4.5 years old

OBJECTIVE(S):

To teach counting and subtraction of the unit place value in a concrete manner seeing the minuend and then taking away the subtrahend:

- Minuend (被减数 [bèi jiǎn shù]): the first number in a subtraction (a quantity or number from which another is to be subtracted).
- Subtrahend (减数 [jiǎn shù]): the second number in a subtraction (the number to be subtracted)
- Difference (剩[Shèng])

MATERIALS:

1. Homemade Addition Board using drawing block and green ribbon, green being the Montessori color for subtraction and making sure that your child associates the color of green with subtraction
2. 1 cup with glass pebbles
3. 1 set of number cards or number tiles (optional)
4. 1 set of equation cards (optional, you can also write the equation on a piece of paper)
5. 1 subtraction worksheet/paper, 1 pencil and eraser
6. 1 mat

PRESENTATION:

1. Lay out the materials on the table.

2. Explain that addition means putting things together and subtraction means taking them apart.

4. Have your child place 7 pebbles onto the minuend section on the subtraction board counting them as you go along. Then point to the number 7 in the problem and say, "You have 7 pebbles." Place the number tile 7 below the pebbles.

6. Transfer 5 pebbles from the minuend to the subtrahend section counting them as you go along, point to the number 5 in the problem and say, "You took away 5 of them. Place the number tile 5 below the pebbles.

8. Ask, "How many pebbles do you have left?"

9. Transfer the 2 pebbles from the minuend to the difference section, counting them as you go along and say, "You have 2 pebbles left. We say 7 take away 5 equal 2." Place number tile 2 below the pebbles.

11. Repeat this process with other subtraction problems.

VIDEO DEMONSTRATION:

J tried this on 17 May 2014 (5y2m12d) for the first time. He was able to do them. We continued with this activity every day. However, J prefers the Singapore Maths Assessment book though to this Montessori subtraction board... children can be very different. It doesn't matter which method as long as they are learning. J had fun coloring the answer from the Singapore Maths Assessment book (so black and white pages can be a blessing after all.)

REFERENCES: 18 May 2014 (5y2m12d) 19 May 2014 (5y2m14d)