Make the following changes to this number 3.587: Make the 3 worth 1/10 as much

Answer 1

3*1 + 5* .1 + 8*.01 + 7*.001
multiply the 3 by .1
3* .1 + 5* .1 + 8*.01 + 7*.001
that is
8 * .1 + 8*.01 + 7*.001
which is
0.887