Working Rules

A science lab has safety rules. A maths lab has working rules. They keep your answers honest.

• Show your steps. A correct answer with no steps cannot be checked, and a wrong answer with steps can be fixed.
• Check the units. 50 g and 50 kg are very different. Write the unit on every answer.
• Estimate before you calculate. If 438 + 476 is about 900, then 804 cannot be right.
• A wrong answer is information. It tells you which idea to look at again. Read “what you should have done” carefully.
• Never rub out your working. Cross it out with one line, so you can see later what you tried.
• Check by going backwards. Check a subtraction by adding, and a division with N = D × Q + R.