The children were learning to recognise and use factor pairs in mental calculations.
The more able children worked on this Nrich activity on factors, on the computers. They had to arrange the four number cards (1, 2, 3 and 21) on the grid to make a diagonal, vertical or horizontal line.
They could put a number card on a square with
• the same number
• a multiple of that number
• a factor of that number.
There were 14 different combinations.