# Foundation BAR MODEL METHOD for PSLE Math

The following two examples and an exercise are part of the Foundation Course at

Primary Four level. The learning involves

1. Understanding Mathematical Situations.

2. Applying Basic Mathematics for appropriate Mathematical Models.

3. Constructing and Organising Bar Models for a Pictorial View.

4. Performing Arithmetic Operations and Algebraic Manipulations for computations.

Ms Tan works 8 hours a day in a toy factory. She can make 5 toys for each of the first six hours and 4 toys in each subsequent hour.

She receives an order for 200 toys. What is the least number of working days she needs for the order?

1. The first bar model shows the possible number of toys made in a day .

2. The next bar model for 200 toys to be made with the largest possible number of toys** **for the least number of days.

3. Finally, we use the corresponding relation to obtain the answer of at least 6 working days as shown.

Cindy and Debra each had a piece of wire of the same length. They made identical wired figures

using a small piece of wire of the same length. Cindy made 35 figures and had 80 cm of wire left.

Debra made 28 figures and had 2.9 m of wire left.

(a) What was the length of wire needed to make each figure?

(b) With the remaining wire from both girls, how many more such figures can be made?

1. Construct a pair of bar models for Cindy’s situation and Debra’s situation.

2. For (a), we compute the length of wire for each figure.

3. For (b), we compute the number of figures which can be made with the two remaining wires.

Albert and Betty had a total of 108 stamps at first.

Betty gave 12 of her stamps to Albert. Albert now has 3 times as many stickers as Betty.

How many stickers did Betty have at first?

1. We begin with the “After” situation (known situation) in which Albert has 3 times as many stickers as Betty and they have a total of 108 stamps.

2. Next, we have the “Before” situation (unknown situation) before Betty giving 12 of her stamps to Albert. and they have a total of 108 stamps.