Write out the calculation (an expression) for Mary’s purchase.
Answer: 12 kr + 2 **·** 5 kr =
12 kr + 10 kr = 22 kr
The example above is an expression which includes two arithmetic operators: addition and multiplication. Actually, it may not be quite clear as to how to do the calculations by simply looking at the expression. Which is actually the correct way?
a) 12 + 2 **·** 5 = 14 **·** 5 = 72
b) 12 + 2 ** ·** 5 = 12 + 10 = 22
You could think like this:
You will be buying the following:
- Chocolate for 12 kr
- Two lollipops for 5 kr each
The expression becomes: 12 kr + 5 kr + 5 kr = 12 kr + 2 **·** 5 kr =
22 kr
The answer 22 is then the right one!
~~a) 12 + 2 ~~** ·**· 5 = 14 **·** 5 =
72
b) 12 + 2 **·** 5 = 12 + 10 = 22 |