1.4290 = 2× 5× 3× 1 1× 13 = (5× 13) × (2× 3× 1 1) = 65× 66.

2. 1= 1? 8=2? 27=3? 2 16=6? As for 126, it should be 125=5? The number in your mouth should be 4? =64

B is proportional to C, and the change of B is the same as that of C.

A is inversely proportional to B, and the change of A is opposite to that of B, so is C.