Countdown is a British game show with a "Numbers" and a "Letters" round. In the Numbers round, a contestant chooses how many random large numbers (25,50,75,and 100) they would like, and then small numbers (1-10, each twice) are randomly chosen to bring the total up to six. Then a random three digit target number is chosen and the contestants have 30 seconds to use their six numbers and the four basic operations ( + - x / ) to make the target. You get 10 points for getting exactly the target, seven points for being with five of the target, and five points for being within 10 of the target. See Nick Berry's very thorough analysis of the game here.