Or use switch!
Switch([isize]<0,0+[exutiss],[isize]<0.3,1+[exutiss],[isize]<0.7,2+[exutiss],[isize]<=1,3+[exutiss],[isize]<2.1,4+[exutiss],[isize]<=3,5+[exutiss],[isize]<=4,6 +[exutiss],[isize]<=8,7+[exutiss],[isize]<=12,8+[exutiss],[isize]<=24,9+[exutiss],[isize]>24,10+[exutiss])
I don't know how many conditions it can hold, but it was all done in a query! Thanks for your help!