Can (1.98 + 2.79) / 0.9 be easily calculated

Can (1.98 + 2.79) / 0.9 be easily calculated

(1.98+2.79)/0.9
=1.98/0.9+2.79/0.9
=2.2+3.1
=5.3

The method of solving equation in elementary school (x-1): x = 5:10

(x-1):x=5:10
5x=10(x-1)
5x=10x-10
5x=10
x=2

X + 10 = (x-20) 2.5 how to solve the equation, please use the method of primary school

Let's take a look at the authentic steps
x+10=(x-20)2.5
X + 10 = 2.5x-50 multiplicative distributive law
(x + 10) = 2.5x-50 take (x + 10) as a number
2.5x = 50 + (x + 10) the subtracted equals the subtraction plus difference
2.5x=50+x+10
2.5x=60+x
2.5x-x = 60 the addend equals and subtracts another addend
1.5x=60
X = 60 △ 1.5 factor equals the product divided by another factor
x=40