The load sits on the left pan — balance it with the weights below the scales; each one can be used only once. Type a weight’s number and press Space: it drops onto the right pan and the scales tilt straight away, so you see at once whether it’s too heavy. Type -7 to take the 7 back off. When the scales balance, the next load arrives. There is usually more than one answer, but using as few weights as possible earns Perfect. In later loads, L7 puts a weight next to the load — it then counts on the load’s side. Stuck? Tab shows an answer. Puzzles: 10 loads, no clock. Market: balance as many as you can in 90 seconds.