Methods similar to this go back thousands of years, at least to the ancient Sumerians and Egyptians. Around 1956, the famous Soviet mathematician Andrey Kolmogorov conjectured that this is the best ...
To multiply two numbers with the same unit places, such as 97 and 98, one can write it as (100-3) x (100-2). Next, add the two numbers 3 and 2 together, which gives 5. Subtract 5 from 100 (as it falls ...