#Idioms
off the top of (one's) head
From memory; without much or careful consideration.
Example:

A: "How much can we expect to earn this quarter?"
B: "Off the top of my head, it should be around $200,000, but I'll have to check the figures when I get to the office."

#Idioms
from scratch
Fig. [making something] by starting from the beginning with the basic ingredients.

do something from scratch;
make something from Scratch;
Start (something) from scratch;

Examples:

We made the cake from scratch, using no prepared ingredients.

I didn't have a ladder, so I made one from scratch.

#Idioms
wrap (one's) mind around something

To comprehend something that one considers challenging, confusing, or a foreign concept.

Examples:
Kate is willing to pay full price for an expensive handbag, but I just can't wrap my mind around that.

#Idioms
go against the grain

meaning: to go contrary to someone's natural disposition

Examples:
“Having to get up this early in the morning really goes against my grain.”
This refers to the fact that someone who rubs his hand against the grain on a piece of lumber will get splinters.

#Idioms
a penny for your thoughts

Meaning;
People say a penny for your thoughts when they want to know what someone is thinking.

Example:
'A penny for your thoughts,' Marina said with a smile.

#Idioms
Ball is in your court

Meaning: It is up to you or it is you turn to make the next decision

Examples:
Well, they invited you, so the ball is in your court now. Do you want to go out with them or not?

#Idioms
**to bury the hatchet**

Meaning: to make peace with someone.

Example:
Can you please bury the hatchet and make up with your sister already? I can't take the constant fighting.