MATERIAL:

- As for addition

PURPOSE:

- To give an understanding of subtraction
- To give the vocabulary: subtraction, minuend, subtrahend, and difference

AGE:

- 4 1/2 years and older

EXERCISE:

- A small group of children. The material is arranged as for addition. One child is in charge of the golden bead material, another the large number cards, and another the small number cards. These subtraction problems will not involve exchanging. The teacher may choose to use one or two subtrahends (the number being subtracted). Below is how the following problem would be worked.
- 4326 minuend

- - 2112 subtrahend

- - 1103 subtrahend
- difference

The teacher tells the children,
"Today we are going to work subtraction problems." The teacher
makes the minuend, 4326, in golden bead material and the large number
cards, and places them
on the mat. She makes the subtrahends, 2122 and 1103, in small
number cards and puts them on two trays.

- She gives a tray to each of two children, Mary and John. She asks the children to read the numbers on their trays. They do so in turn. The teacher then indicates the bead material on her mat and says, "I have 4326. I am going to let Mary subtract 2112 and I am going to let John subtract 1103. Mary, will you subtract 2112?" As the children have not worked subtraction before, she guides them through the process. "How many units do you want, Mary?" "Two." "Yes. You can take two of these units." Mary does so. "How many tens do you need?" "One." "You can take one ten then." Mary continues until she has subtracted 2112 in golden beads. The teacher takes the small number cards 2112 off Mary's tray and puts them under the large ones which form the minuend at the top of the mat. "Now, John, you may subtract 1103. How many units will you take?" John continues until he has subtracted 1103 in golden beads.

- The teacher takes the subtrahend off John's tray, saying, "You
have subtracted 1103." She puts it under Mary's subtrahend at the
top of the mat.

- The teacher then asks a child to count the bead material
remaining on
the mat, and place the corresponding small number cards
underneath.
"We have 1111 left." She superimposes the small number cards, and
places them underneath the subtrahends at the top of the mat to form
the answer of the written problem. The
teacher then reviews the problem. "We had 4326, and Mary
subtracted
2112 from it, and John subtracted 1103. We have 1111 left."

- Introducing the specialized vocbulary, the
teacher may tell the children, "Today we did subtraction. 4326
was the
amount we started with--our minuend.
From that we subtracted our two subtrahends,
2112 and 1103. We call the answer to our problem, 1111, the difference." Pointing to each
set of numbers, she reviews, "Minuend, subtrahend, subtrahend,
difference." She further clarifies the terminology by continuing
with the three period lesson. "Point to the minuend. Which
one is the difference? Point to a subtrahend. Is there
another subtrahend?" Pointing to each set of numbers in turn, she
asks the students, "What do we call this?" The teacher will use
this vocabulary when working additional subtraction problems with the
children.