Excel reusable spreadsheets covering arithmetic

Reusable Excel spreadsheets for Excel / Open Office covering arithmetic, mainly addition and subtraction, but with some multiplication and division; adding and subtracting near mulitiples of 10, 20, 30, etc; effect of mulitplying and dividing by 10, 100 and 1000 including integers and decimals. I.W.B. working models involving exchanging/ renaming/‘carrying’; arithmetic word problems. All sheets can be reused time and again with the press of the F9 key to generate new numbers with related answers (can be displayed on I.W.B. for self-marking) and print to A4 to allow as much practice as required with additional sheets for lessons or extra homework practice.