How much did Isaac reap the year he sowed seed in Gerar?

Answer: A hundredfold

Isaac sowed seed in the land and that very year reaped a hundredfold, because the LORD blessed him.

“So Isaac settled in Gerar. Now Isaac sowed seed in the land, and that very year he reaped a hundredfold. And the LORD blessed him,”— Genesis 26:6, 26:12 (BSB)