Mary needs 6*1= <<6*1=6>>6 folders.
Mary needs 6*3= <<6*3=18>>18 pencils.
Mary needs 18/6= <<18/6=3>>3 erasers.
Mary spends 6*6= $<<6*6=36>>36 on folders.
Mary spends 18*2= $<<18*2=36>>36 on pencils.
Mary spends 3*1= $<<3*1=3>>3 on erasers.
Mary spends 36+36+3= $<<36+36+3=75>>75 on all the supplies except the paints.
Mary spends 80-75= $<<80-75=5>>5 on the paint set.
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