Find the number from each of the following expanded forms : (a) `8 xx 10^4 + 6 xx 10^3 + 0 xx 10^2 + 4 xx 10^1 + 5 xx 10^0` (b) `4 xx 10^5 + 5 xx 10^3 + 3 xx 10^2 + 2 xx 10^0` (c) `3 xx 10^4 + 7 xx 10^2 + 5 xx 10^0`