Balanced+equations

How Many Ways?
You need: Mini whiteboard and marker, calculator. First student writes a simple number sentence in the middle of the whiteboard and draws a circle around it (eg. 2+4). Second student writes a different but equal number sentence in the space left around the circle (4+2 or 1+5 etc.) First student checks the number sentence on a calculator, then writes their own different but equal number sentence. Swap roles of writing different but equal number sentences and checking with calculator until there is no more space to write on the whiteboard. Extend: Only use number sentences with at least two different operations (10+12=16+10-4 or 10+10=3x5+5)