What number is this?

Question

1 x 10(to the third power)+ 3 x 10(to the second power)+ 7 x 10 + 8 x 10 (Minus two to the second power

Answer 1

1 X (10^3) + 3 X (10^2) + 7 X 10 + 8 X 10 (-2^2)
1 X (1000) + 3 X (100) + 7 X 10 + 8 X 10 (4)
1000 + 300 +7 X 10 +8 X 40
1000 + 300 + 70 + 320 = 1690