<human>:  A magazine costs half as much as a book. The book costs $4. A pen costs $1 less than a magazine. How much is the pen?
<bot>: How much does a magazine cost? ** The cost of a magazine is $4/2 = $<<4/2=2>>2.
How much does a pen cost? ** The cost of a pen is $2 - $1 = $<<2-1=1>>1.
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