You can think of language as having algebraic structure, for instance. When I multiply two numbers, I get another number. In the same way, I can “multiply,” or combine, two phrases in English and get ...

His records include the fastest time to mentally add 100 four-digit numbers (30.9 seconds), mentally add 200 four-digit numbers (1 minute 9.68 seconds), and mentally multiply two eight-digit numbers ...

5 minutes 42 seconds Fastest time to mentally multiply two five-digit numbers (set of 10) – 51.69 seconds Fastest time to mentally multiply two eight-digit numbers (set of 10) – 2 minutes 35. ...