Note: Required difference `= (7000-7)=6993`

Note: Required difference `= (70000 - 70) = 69930`

Note: Required Number `= (6581-4991) = 1590`

Note: Let `3500731-x=1735618`. Then, `x=(3500731-1735618)=1765113`.

Note: Let `x-1936248 = 1635773` or `x=(1635773 + 1936248)` `x=3572021`

Note: Required digit = unit digit in the product `(4 xx 8 xx 7 xx 3)` `= 2`

Note: Unit digit in `7^4` is 1. So, unit digit in `7^92` is 1.`:.` Unit digit in `7^95` is 3. [`:.` Unit digit in `1xx7xx7xx7` is 3] Unit digit in `3^4` is 1. `:.` Unit digit in `3^56` is 1.Unit digit in 3^58 is 9 [`:.` Unit digit in `1xx3xx3` is 9] `:.` Unit digit in `(7^95 - 3^58)` is 4. [Subtracting unit digit 9 from unit digit 3 ]

Note: `4^7 xx 7^5 xx 11^2 = (2 xx 2)^11 xx 7^5 xx 11^2` =`2^11 xx 2^11 xx 7^5 xx 11^2` =`2^22 xx 7^5 xx 11^2`.

Note: `(3a + 2b) / (3a - 2b)` = `(3 a/b + 2)/ (3 a/b - 2)` = `(3 xx 4/3 + 2) / (3 xx 4/3 - 2)` = `6/2` = 3. [Dividing Nr & Dr by b ]

Note: Since a , b, c are positive integer and 180 is not divisible by any of `2^3 , 3^3, 4^5` and `5^3`. So , `a^3b ` = 180 is possible only when `a^3` = 1 and b = 180. `:.`a = 1 and b = 180. Now `a^3b ` = abc =>c = `a^2` = 1.