#78.4%# is equivalent to #784# parts out of #1000# or #784 / 1000.#
Find the greatest common divisor (GCD) of these two numbers and divide the numerator and the denominator by the GCD.
GCD Algorithm
#1000 / 784 = 1# with remainder #216#
#784 / 216 = 3# with remainder #136#
#216 / 136 = 1# with remainder #80#
#136 / 80 = 1# with remainder #56#
#80 / 56 = 1# with remainder #24#
#56 / 24 = 2# with remainder #8#
#24 / 8 = 3# with remainder #0#
The last remainder before #0# is the GCD which is #8#.
#784 / 8 = 98#
#1000 / 8 = 125#
Hence #98 / 125# is #78.4%# to a fraction reduced to lowest terms.