Question

Question was provided via image upload.

Explanation:

Step1: Split 6 into 3 and 3

$6 = 3 + 3$

Step2: Subtract first 3 from 13

$13 - 3 = 10$

Step3: Subtract remaining 3 from 10

$10 - 3 = 7$

Answer:

7

To fill the blanks:
First line: $\boldsymbol{13 - 3 - 3}$
Second line: $\boldsymbol{10 - 3 = 7}$
Third line: $\boldsymbol{13 - 6 = 7}$