1024.
Use a calculator if you can't figure it out!
1 and 16 2 and 8 4 and 4
16 and 8. 2 and 64. 4 and 32.
These are the pairs of numbers that when multiplied are equal to 64: (1, 64) (2, 32) (4, 16) (8, 8)
16
16 2*8=16
16 16
1 x 16, 2 x 8, 4 x 4
8*8 2*32 4*16
1 x 32, 2 x 16, 4 x 8, 8 x 4, 16 x 2, 32 x 1
1 & 64, 2 & 32, 4 & 16, or 8 & 8
8
√4 × 16 = ±2 × 16 = ±32 (though the √ symbol normally means the positive square root). √(4 × 16) = √64 = ±8