throwback maths 7

One of those order of precedence questions. Fortunately devoid of ambiguity!

throwback 7
Solution

The old mnemonic of BODMAS / BIDMAS still has some value - but to be of more use, we should think of it as BI(DM)(AS), where the division and multiplication have the same order of precedence as do addition and subtraction.

Our expression will evaluate as follows:

(1) Brackets first

$$10^2 - 5(10-4) + 12 = 10^2 - 5(6) + 12$$

(2) The indices

$$10^2 - 5(6) + 12 = 100 - 5(6) + 12$$

(3) Multiplication or Division

$$100 - 5(6) + 12 = 100 - 30 + 12$$

(4) Addition or subtraction, evaluated left to right

$$100 -30 + 12 = 82$$