A 12-year-old UK-based Nigerian boy, Chika Ofili, has made Nigeria proud by discovering a new mathematical formula that makes division easy.
For his ingenuity, Ofili bagged the TruLittle Hero Award.
In a Pluse.NG report, his mathematics teacher, Miss Mary Ellis who is also the head of the maths department at Westminster Under School said Chika discovered the new formula after a holiday assignment.
She said that she gave Chika a book called First Steps for Problem Solvers (published by the UKMT) to study during the holidays.
The book contained several divisibility tests, which are used to quickly work out whether a number is exactly divisible by either 2, 3, 4, 5, 6, 7, 8 or 9 before you start dividing.
However, there was no test listed for checking divisibility by 7. This was not listed because there is no easy or memorable test for dividing by 7 but Chika Ofili solved this problem.
He discovered that if you take the last digit of any whole number, multiply it by 5 and then add this to the remaining part of the number, you will get a new number. If this new number is divisible by 7, then the original number is divisible by 7.
Chika then demonstrated his new formula in front of the school faculty. Afterwards, Miss Ellis got a neutral mathematics guru to test the theory. This person was Simon Ellis’ younger brother who also taught mathematics.
He tested the theory and wrote an algebraic proof for it. He further discovered that the test works if you start by multiplying the last digit by 12, 19, 26, 33…and then add it to the remaining part of the number.