First, find the easy percentages (1%, 10%, and 50%)
50% is 1/2.
1/2 of 52 is 26. (1/2 of 50 is 25, and 1/2 of 2 is 1. 25+1=26)
10% is just moving the decimal place left one spot.
10% of 52.0 is 5.20
1% is just moving the decimal place left two spots.
1% of 52.0 is 0.520
Now, you can estimate 48% two ways. You can subtract 2% (2x1%) from 50%, or you can multiply 10% by 4 and add 8% (8x1%)
Since it'll be easier to subtract 2 than it will be to multiply by 4 and add 8, we'll subtract.
We'll round 0.52 to 0.5 to make it easier.
Multiplying 0.5 by 2 gives us 1.
26 (50% of 52) minus 1 = 25
48% of 52 is approximately 25.
