For a single textbook, grams is better but for loads of them - for example, a year's worth - a kilogram.
It natters what you're measuring, for you kilograms would be better, because 1 kilogram is about 2.2 pounds. A 175 pound man would weigh 79378.66 grams and 79.38 kg so obviously a gram is good for something with a small mass.
Kilograms.
grams
Kilograms because 1 kilogram is 1,000 grams and trucks are very heavy.
Neither. Both gram and kilograms are units for measuring mass, not weight. The weight would be measured in Newtons.
It would be more appropriate to measure 5 math textbooks in grams or kilograms, as they are smaller and more suitable units for measuring the mass of books. Milligrams would be too small a unit for this measurement.
It natters what you're measuring, for you kilograms would be better, because 1 kilogram is about 2.2 pounds. A 175 pound man would weigh 79378.66 grams and 79.38 kg so obviously a gram is good for something with a small mass.
Kilograms.
Grams, milligrams, kilograms, etc...
grams or kilograms (more often)
10 grams is the better estimate of the weight of a crayon.
grams
Grams is better.
Kilograms because 1 kilogram is 1,000 grams and trucks are very heavy.
7 grams
Neither. Both gram and kilograms are units for measuring mass, not weight. The weight would be measured in Newtons.
I think using grams is better, because it may not come more than 5 kilograms