If Toni, Who Is Only Six Years Old, Is Asked

Multiple Choice

If Toni, who is only six years old, is asked what she would get if she added 5 and 10 together, which of the following processes would she most likely use?

A) ​She would break the ten down into two fives and then add five together three times.
B) ​She would start with five and add ten by increasing the sum, one number at a time (e.g., "five, six, seven, eight…") .
C) ​She would already have memorized that the sum is 15, so she would simply retrieve it form memory rather than calculating the answer.
D) ​She would start with ten, and add five by increasing the sum one number at a time (e.g., "ten, eleven, twelve…") .