Which is a bigger problem and why- sexism or racism?

Sexism ...it can effect half the worlds population.......racism ,not nearly as much.....

Men seem to put a women down all the time......far more often though if their heavy...... :( D

First, can you define those terms?

And second, why should either be considered a problem?

I think that racism is a much bigger problem. People hate each other because of the color of their skin or where they came from, is far worse. It affected our last election. In the last 50 years race relations have improved,  but there is still a lot of hate and with black lives matter- police officers shooting unarmed black men, people protesting in the streets, getting hurt, nazi...its creating controversy at sporting events, its a huge issue and nothing is being done to change the situation, looking back to the LA riots , quoting Rodney King,  "can't we all just get along?"

Sexism. You can avoid people of a different race if it bothers you, but ducking half the world's population is harder.

OK, let's start with sexism, seeing as how you don't seem to want to deal with both concepts at the same time. 

What is sexism?
Is that when a man happens to pass by a lady and makes a positive comment about her appearance? Maybe he says you look absolutely fantastic today. Is that him being sexist?

And what if a woman passes by a workman in the street wearing a thin T-shirt (it's the middle of summer for the sake of this question) and she says something like "You look really hot today (it's 95-degrees F and he's sweating, or maybe not?), great 6-pack you've got there." Is that her being sexist?

Context determines whether race or gender differences determine advantage or disadvantage.

A woman seeking a promotion or better paid work faces obstacles that a man does not face, regardless of her skin colour. But statistically in the USA, a black person seeking higher office encounters barriers that a white person doesn’t, no matter his gender. 

But racial or gender-specific disadvantages have different effects and are hard to measure. Which is worse, sexual harassment, racist slurs or ostracism? 

Surely the stress and the long term effects are equally destructive. 

An thinking both are problematic...
on one hand Sexism
on the other hand Racism
Isms just basically suck...

Both are abhorrent and destructive.  Both equally,  however I'd say racism is my answer since sexism is purely a sociological and man-made construct while racism has an evolutionary biological survival mechanism to it.  Being a somewhat ingrained trait inprinted in our genes I think means makes it harder to conquer and keep from springing up again when certain conditions are in place.