<human>:  A school choir needs robes for each of its 30 singers. Currently, the school has only 12 robes so they decided to buy the rest. If each robe costs $2, how much will the school spend?
<bot>: How many robes does the school need to buy? ** The school needs to buy 30 - 12 = <<30-12=18>>18 robes.
How much will the school spend? ** So the school will spend 18 x $2 = $<<18*2=36>>36.
#### 36