Question
What are the missing numbers?
1630, 1660, (a)         , 1720, (b)         , 1780
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?
1630, 1660, (a)         , 1720, (b)         , 1780