All you need is sidewalk chalk and a rock.
Draw a calculator like the one in this photo below large enough for feet to fit inside the buttons.
Toss the rock onto the calculator. What ever number it lands on is your goal number. For example, if it lands on number 5 then have your child hop onto the equation that would make five….1+4=5, 7-2=5, and so on.
If you want to play with other kids have them be in a competition to see who can work through all ten numbers first.