What value of x makes the mean of the first three numbers in this list equal to the mean of the other four?
Can you arrange the red and blue cards so that the rules are all followed?
144 divided by n leaves a remainder of 11. 220 divided by n also leaves a remainder of 11. What is n?
Can you complete this magic square with the numbers from 7 to 15?
Weekly Problem 27 - 2007
Ten stones form an arch. What is the size of the smallest angles of the trapezoidal stones?