<human>:  There were 21 dollars in the cookie jar. Doris spent $6 from the cookie jar. Martha spent half as much as Doris. How much money, in dollars, was left in the cookie jar?
<bot>: How much did Martha spend? ** Martha spent 6/2=<<6/2=3>>3 dollars.
How much did Martha and Doris spend? ** Martha and Doris spent 6+3=<<6+3=9>>9 dollars.
How much money was left in the cookie jar? ** There were 21-9=<<21-9=12>>12 dollars left in the cookie jar.
#### 12