molar problem!!!

$KMnO_{4} =$ Potassium Permanganate

Consists of: $KMnO_{4}$

$1) K$

No. of atoms $=1$

Atomic mass $=54.938$

Total mass $=54.938\times1=54.938$

$2) Mn$

No. of atoms $=1$

Atomic mass $=39.098$

Total mass $=39.098\times1=39.098$

$3) O$

No. of atoms $=4$

Atomic mass $=15.999$

Total mass $=15.999\times4=63.996$

So, mass of $KMnO_{4} = 54.938+39.098+63.996=158.032=158$ (approx.)

Thus, the answer is $= \boxed{158}$

Mass of oxygen is 16 so 16*4=64 then add the masses of K and Mn that is 55 and 39 respectively.