mysql fulltext hunt measure explained

i've experimenting fulltext hunt newly am extraordinary definition measure value. instance i have following query:

select table. * ,
match (
col1, col2, col3
)
against (
'+(term1) +(term1)'
) score
from table
where review (
col1, col2, col3
) 
against (
'+(term1) +(term1)'
)

in law measure i've seen results, query, between 0.4667041301727 11.166275978088. i it's mysqls thought aptitude (the aloft some-more weight).

what i don't mysql comes adult score. since array returned decimal something besides ?

how i run query "in boolean mode" does measure always relapse 1 0 ? wouldn't law 1?

just anticipating enlightenment. thanks.