<human>:  A school bought 20 cartons of pencils at the start of school. Pencils come in cartons of 10 boxes and each box costs $2. The school also bought 10 cartons of markers. A carton has 5 boxes and costs $4. How much did the school spend in all?
<bot>: How many boxes of pencils did the school buy? ** The school bought 20 x 10 = <<20*10=200>>200 boxes of pencils.
How much did the pencils cost? ** The pencils cost 200 x $2 = $<<200*2=400>>400.
How many boxes of markers did the school buy? ** The school bought 10 x 5 = <<10*5=50>>50 boxes of markers.
How much did the markers cost? ** The markers cost 50 x $4 = $<<50*4=200>>200.
How much did the school spend in all? ** Thus, the school spent a total of $400 + $200 = $<<400+200=600>>600.
#### 600