Scott earned $120 babysitting. He saved 45% of his money. Use mental math to find how much he saved.

Step-by-step answer:

Question requests use of mental math.

When calculating 45%, we use the fact that 45% is 90% of 50%, or

45% can be obtained by subtracting 1/10th of half the amount.

Thus 45% of $120 is obtained by

subtracting 1/10th of half of $120, which is

subtract 1/10th of $60

which in turn gives 60-6 = $54.

no calculator is required.

Scott saved $54

Step-by-step explanation:

The simple way to do is to find the 45% of the total money and that is what Scott has saved

So

45% of $120 would be = (45 / 100) * 120

45% of $120 would be = 54

So he saved $54 and he has $66 with him now