Which kind of yeast?
A packet of dry yeast is 1/4 ounce.
A cake of yeast is heavier.
Either of these is equal in leavening power to 2.25 teaspoons of bulk granular yeast (either active dry or instant active dry.)
When you open a brick of bulk granular yeast, that pound of yeast explodes in size to more than a 3 pints.
Because you don't specify what you're asking, there is no answer.
And there's a lot of "give" in recipes. Yeast multiplies over and over until the entire recipe has been "infected" with the yeast. That's not just my observation, either - the book of Galations advises us that a little leaven leaveneth the whole lump.
In baking, I use 1/2 to 3/4 of a tablespoon to start my sponge. Even keeping the yeast in mason jars in the fridge, I end up throwing it away after about a year more out of paranoia that it's going weak than any observed change in the baked goods. A pound of yeast costs what, about $3? I figure that's far cheaper than throwing away baked goods worth $10 or $15.
1 tablespoon (tbsp) = 14.235 grams
http://gourmetsleuth.com/gram_calc.htm
Approximately 1/2 tsp equals 1 gram yeast
There are 15 grams in 1 Tablespoon.
One tablespoon of active dry yeast is approximately 1/3 of an ounce. There are 28 grams in an ounce, so one tablespoon is approximately 9 grams.
14.235 grams = 1 tablespoon
8 grams of yeast (metric) is 0.5 tablespoons.
1 tablespoon = 15 grams
1 tablespoon = 15 grams
1 tablespoon = 15 grams
1 tablespoon = 15 grams
15 grams are available in 1 tablespoon crackcorn.
1 tablespoon = 15 grams of water
That is 1/3 tablespoon.
1 tablespoon is about 14 gm yeast. 40 gm is a fraction less than 3 tablespoons.