Let the decimal digit of the original number be x, and the unit is (x+3).

[ 10x+(x+3)]X7/4 = 10(x+3)+x

( 1 1x+3)X7/4 = 1 1x+30

( 1 1x+3)X7 =( 1 1x+30)X4

77x+2 1=44x+ 120

33x=99

x=3

x+3=3+3=6

The original number is: 36.