Exercise 9 Page 115

We want to estimate 0.4 % of 510. We will start by rounding 510. rcl 510 & ≈ & 500 Now we can find 0.4 % of 500 to get an estimation. To do so, let's start by finding 1 % of 500 by multiplying these two quantities. Recall that 1 % is equal to 1100.

We found that 1 % of 500 is equal to 5. Now let's find 0.4 % of 500. We can do this using the fact that 0.4 % is 0.4 of 1 %. rcr 1 %of 500 & = & 5 [0.3em] & ↓ & [0.3em] 0.4of 1 %of 500 & = & 0.4of5 [0.3em] & ↓ & [0.3em] 0.4 %of 500 & = & 0.4of5 Finally, let's calculate 0.4 of 5 by multiplying these two numbers. This will give is the desired estimation.

We found that 0.4 % of 510 is about 2.