I guess so yeah.

"sizes" are usually known by the ounce. 1 ounce=28grams. It is a unit of weight and there is no other way around it.

1ounce=28grams
1/2 (half) ounce=14grams
1/4 (quarter) (which is half of a 1/2 ounce)=7grams
1/8 (eigth) (which is half of a 1/4)=3.5grams

Anything lower you have to do the math, which may require some thinking.

If you want half of an 1/8, do the math, which is 3.5grams/2, which is approx. 1.7grams, if you want half of 1/16(1.7g's), again, divide 1.7 by 2.

It's all simple math really. Have fun! Bye.