Where can I play a countdown game online?

Two websites where users can play a countdown game include Subtangent.com and Nrich.com. Countdown games allow players to select a group of six random numbers and a target number. Players must then use addition, subtraction, multiplication or division to reach the target number.

Subtangent's countdown game requires players to select three large numbers (25, 50, 75 or 100) and three small numbers (10 or lower). On Nrich, players have slightly more options, with the ability to select wider combinations of higher and lower numbers. On Nrich, it is possible to select six small numbers and no large numbers or up to four large numbers and two small numbers. Nrich allows players to see the solutions to the problems, whereas Subtangent does not.