Question
What are the missing numbers?
4031, (a)          , 4071, 4091, (b)          , 4131
2 m
(a)

Click button first when a symbol is required. X

(b)

Click button first when a symbol is required. X

What are the missing numbers?
4031, (a)          , 4071, 4091, (b)          , 4131