Statements such as

size = 100
size = size + 2 * spacing

are called assignment statements.

The right hand side of the size = size + 2 * spacing statement is a mathematical expression.

Assignment statements are also valid for text variables

courseName = "Boun102”
courseName = "Boun" + "102"

where the right hand side of the latter is not a mathematical expression, but a string concatenation.

The left hand side of both assignment statements are called variables, named size and courseName respectively.

In python, multiple variables can be assigned in a single assignment statement

a, b = 100, 450

print("a :", a)
print("b :", b)

c, d, e = 200, 250, 300

print("c :", c)
print("d :", d)
print("e :", e)

f, g = a, d

print("f :", f)
print("g :", g)

a, d = 50, 60

print("a :", a)
print("d :", d)

print("f :", f)
print("g :", g)

The values of two variables can be swapped easily in Python without the need for a third variable

a, b = 100, 450
print("a :", a)
print("b :", b)

a, b = b, a

print("a :", a)
print("b :", b)