Tap where the number belongs on a blank number line. The closer you are, the more points you score. Ten numbers a round.
Knowing that 67 sits "just past two thirds of the way" along a 0 to 100 line is called number sense, and it quietly powers estimation, rounding, fractions and mental arithmetic. Children with strong number sense sanity check their 11+ answers instinctively; this game trains exactly that.