Start by rounding 82 and finding 1 % of the rounded number.
About 0.4
Practice makes perfect
We want to estimate 12 % of 82. We will start by rounding 82.
rcl
82 & ≈ & 80
Now we can find 12 % of 80 to get an estimation. To do so, let's start by finding 1 % of 80 by multiplying these two quantities. Recall that 1 % is equal to 1100.
We found that 1 % of 80 is equal to 0.8. Now let's find 12 % of 80. We can do this using the fact that 12 % is 12 of 1 %.
rcr
1 %of 80 & = & 0.8 [0.3em] & ↓ & [0.3em]
12of 1 %of 80 & = & 12of0.8 [0.3em] & ↓ & [0.3em]
12 %of 80 & = & 12of0.8
Finally, let's calculate 12 of 0.8 by multiplying these two numbers. This will give is the desired estimation.
