A binary search looks for 37 in the numbers from 1 to 100 (in order)…

Plan. Each step looks at the middle and halves the range.

1. The middle of the whole range is $50$. $37 < 50$, so keep the lower half.
2. The middle of that is $25$. $37 > 25$, so keep the upper part.
3. The middle of that is $37$. Found.

Answer: $3$ steps for $37$. In the worst case, $7$ steps, because $2^7 = 128$ is the first power of $2$ above $100$.