When our elder 2 boys get on with their maths work in the morning, our youngest son expressed his desire to have a similar workbook of his own. Today his page was presenting number bonds to 10 and I was surprised how quickly he grasped the idea. We started with those he knew .... 5+5, 0+10. He then went and got 10 Duplo blocks and we grouped them - 2+8, 3+7, 4+6, 1+9. He then made a up a little game giving me half the bricks and himself half. He then gave 1 more to me and said, "Now you have 6 and I have 4" and he went on like that, practising all the number bonds completely self-initiated.