ABSTRACT
Ask the children to complete the difference square (Photocopiable Sheet E). This is used in the same way as an addition square. Start by reading the first number in the horizontal line, finding the difference between this and the first number in the vertical line. The difference between 10 and 10 is 0. Write this number in the appropriate square. Then find the difference between the second number in the horizontal line and the first number in the vertical line. The difference between 9 and 10 is 1.
