"Feynman proposed that first-graders learn to add and subtract more or less the way he worked out complicated integrals — free to select any method that seems suitable for the problem at hand. A modern-sounding notion was, The answer isn’t what matters, so long as you use the right method. To Feynman no educational philosophy could have been more wrong.
"The answer is all that does matter, he said. He listed some of the techniques available to a child making the transition from being able to count to being able to add. A child can combine two groups into one and simply count the combined group: to add 5 ducks and 3 ducks, one counts 8 ducks. The child can use fingers or count mentally: 6, 7, 8. One can memorize the standard combinations. Larger numbers can be handled by making piles — one groups pennies into fives, for example— and counting the piles. One can mark numbers on a line and count off the spaces — a method that becomes useful, Feynman noted, in understanding measurement and fractions. One can write larger numbers in columns and carry sums larger than 10."
- James Gleick, from the book Genius: The Life and Science of Richard Feynman