13+15=31
10*10=100
6*3=24
I dont understand base seven and I need to understand this for geometry thankyou for your help

This is 10+12=22 but in base 7.

>10*10=100

This is true in any base, 7 in particular.

>6*3=24

This 6*3=18 but in base 7.

>I dont understand base seven.

So you understand any base other than 10?

>and I need to understand this
>for geometry

How that?

> thank you for your help

There is plenty of information at this site about various bases. Have you read anything?

You can start here

knot.org/Curriculum/Arithmetic/ArithmeticOperationsInVariousBases.shtml

and follow the links.

The main thing to remember is that in base 7 there are only seven digits: 0, 1, 2, 3, 4, 5, 6.