Rocks

 

Dylan has 3 balls. Carlos has 4 more rocks than Dylan. Jake counted his rocks and said, "I have 2 fewer rocks than the two of you have together How many rocks do the boys have altogether?     

 

D  =  3      

C  =  3 + 4  =  7     

J  =  (3 + 7) – 2  =  8     

 

D + C + J  =  3 + 7 + 8  =  18     

_.