Estimate the product 80 * 26

Looks long but it is very fast actually

26 is 25+1

Multiply by 25 is like * 100 and / 4 (because 25=100/4)

So you can see very quick that 80 * (25+1) equals 80*25+80

which is 80*100/4+80 or 80/4*100+80

So it equals 20*100+80 which you can calculate very fast to 2080

Hope you see how this is done fast

You estimate it to be 80 times 30 because it is easier to do. This equals 240.