解设这个数为x
由一个数与3又4分之1的差是1又5分之6,
则x-3又1/4=1又6/5
即x=3又1/4+1又6/5
=3+1/4+1+6/5
=5+1/4+1/5
=5+5/20+4/20
=4又9/20
即x=4又9/20