LESSON 2

Basic Operations

Keys:

+ Add – Subtraction

x Multiply ÷ Divide

= Equal [(-- Left Grouping

--)] Right Grouping +/– Positive and Negative

Decimal

Try This: Enter Display

1. 2 + 28 – 12 = 2 + 28 – 12 = 18

2. 16 x 21 = 16 x 21 = 336

3. 27 ÷ 6 = 27 ÷ 6 = 4.5

4. 12 x (5 + 6) = 12 x [(-- 5 + 6 --)] = 132*

5. 12 x 5 + 6 = 12 x 5 + 6 = 66*

* Notice the results of problem 4 and 5 are different. The order of operation requires that the operations in the parentheses are calculated first.

Lesson 2 continued

Try this Enter Display

6. -3 + 12 = 3 +/– + 12 = 9

or – 3 + 12 = 9

7. 12.345 + 3.2 = 12 345 + 3 2 = 15.545

8. -12 x 5 = 12 +/– x 5 = - 60

More on order of operations.

A scientific calculator will follow the order of operations rule.

Enter 15 + 3 x 7 =. If your calculator displays 36, it is a scientific calculator. If it displays 126, it is not following the proper order.

Try this Enter Display

8. 7 · 8 – 4 · 5 = 7 x 8 – 4 x 5 = 36

*9. = 6 ÷ [(-- 4 x 5 --)] = 0.3

10. 2[7 + 6(5 + 4)] = 2 x [(-- 7 + 6 x [(-- 5 + 4 --)] --)] =

122

*Reminder: The fraction bar is division and you need grouping symbols to calculate properly.