I guess this was: "9999=4,8888=8,1816=3,1212=0,1919=?"
Count the number of complete circles in each number. 8 is formed of two circles, so 8888=8 circles. 6 contains one circle so 1816 contains 3 circles, 1816=3. There are no circles in 1212 and 1919 contains two circles, so 1919=2.