x+3/10=2 over 5 what does x equal

$$\\\frac{x+3}{10}=\frac{2}{5}\\\\
10\times\frac{x+3}{10}=10\times\frac{2}{5}\\\\
x+3=2\times\frac{2}{1}\\\\
x+3=4\\\\
x=1$$

OR

$$\\x+\frac{3}{10}=\frac{2}{5}\\\\
x+0.3=0.4\\
x=0.4-0.3\\
x=0.1\\$$

The way i do it is I multiply everything by 10 to get rid of the denominators, so (x + 3/10) * 10 and (2/5)*10.  That gets you 10x + 3 = 4.  subtract 3 from both sides to isolate x so 10x = 1.  Divide both sides by 10 so 10x/10 = 1/10.  That leaves you with x = 0.1 if you simplify 1/10.  Plug it back in to check.  0.1 + 3/10 = 2/5.  2/5 = 0.4 if you simplify.  3/10 = 0.3 if you simplify.  0.1 +0.3 = 0.4.  0.1 + 0.3 Does add up to 0.4, so x = 0.1.

x+3/10=2                                    17+3/10=2

*10     *10                                     20/10=2

x+3=20                                           2=2

-3    -3

x=17

x+3/10=2/5                                    1+3/10=2/5

*10     *10                                     4/10=2/5

x+3=4                                           2/5=2/5

-3    -3

x=1