drop the whole number and leave the decimal part of the number for calculations

i dont get how you get the last part
=MOD(A1,1)=0.535663
MOD(A1,1)*60 = 32.13978
=MOD(MOD(A1,1)*60,1)= 0.13978
=MOD(MOD(A$1,1)*60,1)*60 =8.3868
shouldn't it be degree mins seconds using this method
The whole units of degrees will remain the same (i.e. in 121.135° longitude, start with 121°).
Multiply the decimal by 60 (i.e. .135 * 60 = 8.1).
The whole number becomes the minutes (8').
Take the remaining decimal and multiply by 60. (i.e. .1 * 60 = 6).
The resulting number becomes the seconds (6"). Seconds can remain as a decimal.
Take your three sets of numbers and put them together, using the symbols for degrees (°), minutes (‘), and seconds (") (i.e. 121°8'6" )

=INT(A1)&" degrees "&INT(MOD(A1,1)*60)&" mins "&MOD(MOD(A1,1)*60,1)*60&" seconds"
or rounding down
=INT(A1)&" degrees "&INT(MOD(A1,1)*60)&" mins "&ROUNDDOWN(MOD(MOD(A1,1)*60,1)*60,0)&" seconds"
or just put each bit in a seperate cel
eg
b1=INT(A1)
c1=INT(MOD(A1,1)*60)
d1=MOD(MOD(A1,1)*60,1)*60