72 Get 80 to be safe.
111 if you can cut 10 exactly in half to make 20 half pavers
It depends on the units used to measure the pavers: inches, centimetres, cubits, etc. It is not possible to answer the question without that information.
16 inch x 16 inch = 16x16/144 = 1.777777.... sq.ft. 450/1.777777..... = 253.125 tiles (not counting any wastage caused by cutting, breakage, etc) = 254 tiles minimum.
The patio is 10x 12 = 120 sq ft or 17,280 sq in The pavers are 16x16 = 256 sq in So you need 17280/256 = 68 pavers
(32 x 16 x 16)/144 ie just under 57 sqft
The answer depends on the measurement units used for 16x16. The answer also depends on the shape of the 390 sq ft area to be covered because the more irregular the shape, the greater the number of pavers you will need to cut. That is likely to result in some breakage. Furthermore, you may not want to use all the offcuts since that will make part of the area into a mosaic.
4.5 pavers will cover 1 sq foot. So 4.5 x 360 =1620 pavers