A good friend of mine came up with this idea and it was used successfully in my observed lessons when I was on teaching practice.

Make a cardboard crown (big enough to fit your children's heads) and decorate with coloured pom poms, metallic card, sequins etc... The crown / hat can be used in maths oral and mental starters to practice number bonds.

A child at the front of the class wears the hat and the teacher blue tacks a number from 0 - 10 on the front of it, keeping it hidden from the hat wearer. The rest of the class looks at the number and works out what they need to add to it to make 10. They could show the answer on their fingers or a number fan.

The hat wearer then knows what they must add to the number on the hat to make 10 so they can work out the hidden hat number. e.g. number on the hat is 6, the class hold up 4 fingers. The hat wearer works out what they need to add to 4 to make 10 and this is the number on the hat. You could extend this to practising number bonds to 20, 50, 100, 1000 etc or even blue tack a 2D shape to the hat and the class gives the hat wearer clues so they can work out what shape is on the hat (e.g. this shape has 3 corners).

The number hat can be used for any activity involving guessing what the hidden number, shape, coin is.

The children love this activity and you can bribe the children to behave if they want a turn at wearing the hat!