<human>:  There are 3 meatballs on each spaghetti plate. If Theresa's 3 sons each eat two-thirds of the meatballs on their respective plates, how many meatballs are still left on their plates altogether?
<bot>: How many meatballs are on the plates altogether? ** Total meatballs on the plates 3 x 3 = <<3*3=9>>9.
How many meatballs are left on the plates altogether? ** If two-thirds are eaten, one-third remaining on the plates is 9 / 3 = <<9/3=3>>3.
#### 3