4 crossword challenge

It is the result of a multiplication
It can be used to represent an infinity of numbers
you use me when you can't convert meters to kilometers (two words merged)
i need to be found to use the Pythagorean theorem (two words merged)
This is the chosen number divided by 2.
a unit which measures how heavy a person or object it
used to measure the size of an object or a distance
family of numbers serve to calculate the age of my mother (two words merged)
unit of temperature
a metric unit of length equal to 1,000 metres
unit of time which is equal to 60 seconds
A way to transform one unit into another.
it's something we have to solve
operation when you use the word "times"
result of an addition.
is a geometric shape who look like a peace of pizza. (two words merged)
way to present the ersult of two intergers division
I have many sides and not only good ones
Like a normal science but cooler
Shape of a football ground
Shape of the moon, every 29 days