A more comfortable way to add and multiply
The nice thing about numbers is that they never lie. It is us who have stopped being fluent in our arithmetic thought due to the availability of calculators, computers and hundreds of other gadgets.
The question is... Do we still know how to add?
When trying to add 123 + 45, for example, most people operate adding the units first: five plus three makes eight, two plus four makes six and all makes a hundred sixty-eight.
Is that OK? Yes, it is. But there is another, more natural, way to make calculations than the old traditional school:
A hundred twenty-three plus forty makes a hundred sixty-three, plus five, makes a hundred sixty-eight.
Leaving the calculator behind (for a while) will definitely help us to strengthen our mathematical reasoning capabilities; but, sincerely, didn't you realize the second way to add is more comfortable than the first one?
Something similar applies when multiplying small numbers: 12 x 45 can be solved like this: forty-five by ten makes four hundred fifty; plus ninety (forty-five times two) makes five hundred forty... easier again than multiplying five by two and then five by one, etcetera.
Knowledge + Mathematics