From weareteachers.com

Use chalk to make a hopscotch board and write addition, subtraction, multiplication or division facts in each square to say as you hop down the board. If you just write the numbers (1,2,3,…) in the boxes, you choose a different to add, subtract or multiply. If you chose multiply by 3… you land on the box with a 4, multiply 3×4. You land on the box with a 7, then multiply 3×7.