Find appropriate number fill in the blanks

Question

Find appropriate number fill in the blanks

Answer 1

Here is one option:

• Take the only number that appears twice in the small circles of a diagram
• Add that pair of numbers, subtract one from the result, and put it in the big circle

a) $3+3-1=5$

b) $18+18-1=35$

c) $43+43-1=85$