No.1 is a fun, interactive math game that challenges players to use mathematical operators to create an expression that equals the number 221. By clicking on the operators (+, -, ×, ÷), players can change the equation to reach the desired result. For example: @2+7+9+4=1 can be changed to @2×7-9-4=1. No.1 can be completed in a few minutes, making it a great way to pass the time. An iPhone version is also available.