Comment You're doing too much work! (Score 1) 845
Finally time for the correction to my not knowing my 47 times table. I knocked off 3*3 to give me the easy 150, so just need to take the 9 off to give the 141.
On multiple choice tests, always read the answers first, and identify the key differences. Here, the options are:
141
1,175
3,525
4,700
And it should immediately jump out that one of these is an order of magnitude lower than the others. So, you know right away that either you can throw this one out or it's the right answer. As soon as you reduce he problem to 47 times 3, you know it has to be that one. Mark A and move on to a harder question. (You can check your work later if you have time.)
If the answer had a higher order of magnitude, the next thing to consider would be whether the answer is likely to be the nice, round 47 times 100 -- another easy-to-identify possibility.