Dan has $ 4. He bought a chocolate for $ 7 and a candy bar for $ 2. How much money did he spend to buy chocolate than he did to buy candy bar?
: 

Dan has $4. 
He buys a chocolate for $7. 
That leaves him with -$3. 
He buys a candy bar for $2. 
That leaves him with -$5. 

So, he spent $2 more on the chocolate than he did on the candy bar.