He said some children had been struggling with non-standard calculations, such as the grid method for multiplication - a confusion which had sometimes been reflected in their test results.
He said: "The grid method requires the children to have to go through 15-20 stages for relatively simple computations. "That meant there were many opportunities for mistakes to be compounded. Pupils were sometimes missing out (in tests) on marks given for working out - something I think we all pray they will at least get."
He said the updated guidance would not stop non-traditional techniques being taught. Such methods would still be used to help children to understand the maths behind the standard methods.
"The idea that mathematical thinking will be stifled by trying to teach children the standard method is nonsense. That is not how teachers teach.
"No good teacher is going to bang away with the standard method if the child does not seem to understand it. It's possible to teach using a standard method, but find different ways of helping them see how that works."
He said that reducing the number of methods available to pupils would make maths simpler for them.
"If you talk to adults and ask them what their bete noir was at school, most will say maths.
"One of our goals has got to be ensuring that pupils will not leave school with a lack of confidence in their mathematical ability, which can come from having a deluge of methods at their fingertips."