Order of Operations Years 2 - 6

Materials

• One MathMaster or MathMate per child
• One other four function calculator which doesn't have the Algebraic Operating System (AOS) built in (most of them don't - the obvious sign of AOS is brackets on the keypad)
• One Poly Plug 5x5 per child

Procedure

Enter the following into your calculator in the order shown: [6] [+] [3] [x] [4] [=]

If it gives the answer 36, it is wrong. The MathMate or MathMaster are simple four function calculators which have been programmed to apply the order of operations.

Teachers use the MathMaster and an ordinary calculator to pose a problem like this to deliberately generate two answers in the classroom and initiate a discussion of the order of operations convention. Poly Plug is used to make a model of the different ways the calculators are thinking.

Teachers go on to discuss how the use of brackets avoids confusion and encourage students to invent 'problems' where it would be appropriate to use (6 + 3) x 4 and where it would be appropriate to use 6 + (3 x 4).