In VB, the value of the expression SQR (100) * 8 / 5 is

In VB, the value of the expression SQR (100) * 8 / 5 is

=10*8/5=16

What is SQR in VB?
I began to learn VB yesterday. There is a place I don't understand in Chapter 3. I hope you can appoint me. Thank you first
Coefficient of dim a as double 'A.B.C equation
Dim b As Double
Dim c As Double
Dim X1 as double 'x1x2 is the root of the equation
Dim x2 As Double
Dim result as double 'result is a formula
Private Sub Form_ Click()
A = 3'abc assignment
b = 8
c = 2
Result = SQR (b * B - 4 * a * c) 'formula
X1 = (- B + result) / (2 * a) 'calculation result
x2 = (-b + result) / (2 * a)
Print X1 'displays the calculation results
Print x2
End Sub
The display calculation result is equal to -. 279240779943873
-.279240779943873
Well, I didn't learn math well, that one
result = Sqr(b * b - 4 * a * c)
Does it mean result = SQR (40)?
What's the meaning of SQR? How to calculate it?
Please teach me, thank you

SQR 1. In most programming languages, SQR (x) stands for the arithmetic square root of non negative number x; [1] 2. In Pascal language, SQR (x) stands for the square of X

What is the SQR of VB
Why can't n be divisible by any number in 2-sqr (n) in a program to determine whether it is a prime number? N is a prime number. What does this SQR represent? Doesn't it mean to return the square root? Is this related to a prime number?

Yes, for example: 17 is a prime, then SQR (17) = 4.123, of course, will be rounded to 4. Take 17 divided by 2, can not be divided, and then 3,4, still can not, then after 5 do not need to calculate, because it is greater than the square root of 17 4.123, can be determined to be a prime