Page 4 - Geometric Patterns

(c)

(d)

7.3 Do not count – calculate!

When we count many objects, it can A plan describes
take a very long time and we may make your method.
mistakes! You can write a plan
A better way is to first write down your in words, as a
calculation plan
thinking as a calculation plan. Write or as a flow
down what you are going to do. diagram.

Then you can calculate the answer
instead of counting. For example:

Amir: Number of beads = 5 + 3 + 5 + 3 + 5 + 3 + 5 + 3

Mia: Number of beads = 5 + 5 + 5 + 5 + 3 + 3 + 3 + 3 = 4 × 5 + 4 × 3
Thea: Number of beads = 8 + 8 + 8 + 8 = 4 × 8

For each bracelet on the next page, write down your calculation
plan to find out:

(a) how many yellow beads there are 4 × 5 + 4 × 3 and
(b) how many green beads there are 4 × 8 and 5 + 3 etc.
are calculation plans.
(c) how many beads there are altogether. A calculation plan
says what calculations
Note: Do not calculate now. The method we are going to do
(plan) is the important thing! You can before we actually do
calculate later or even use a calculator them.
once you have written down your plans.