Very impressive, Albert. Rounding numbers to the nearest 1, 10 or 100 can help with lots of mental maths problems. To add 9 to another number, add 10 and then subtract 1: 36 + 9 = 36 + 10 - 1 = 45 ...
Mental addition and subtraction with Geordie Pigeon. videoMental addition and subtraction with Geordie Pigeon Let the Geordie Pigeon explain how to do mental maths, with this song and movement ...