Is it normal for flames to come up through the slots on each side of the bottom of the oven? They only come up when the burner is on. If not what do I do about it?
Depends on the design of the oven, but yes, this can be normal. If you mean 'in the oven itself, some flames are visible below the plate at the bottom'. If you mean 'outside the oven, flames shoot out of the sides', then you should probably avoid using that oven if at all possible.
An old gas oven I had did this. When the auto-sparker failed, I lit it manually with a fire-lighter using the vents in the base of the oven, and it worked fine.
It sounds like your oven is functioning as it should, in principle. Most ovens have a diffuser plate over the flame elements to spread the heat evenly throughout the chamber, as well as preventing open flame from entering the cooking environment. If your oven is old, it could be lacking such a plate.
If the flames are mostly bluish, these should be considered normal and assumed to be part of the oven's design and function. Should the flames be dark red or orange, and giving off smoke, your oven is more than likely quite dirty, as such these are soot/grease deposits burning off. Brave chefs might take cleaning the elements into their own hands, but your best (and definitely safest) bet would be to get the oven inspected by a professional.
It depends, If you see the top of flame barely peeking through the slot, it’s probably nothing, oven burner ports probably just need cleaning or there might be a little grease that needs to be cleaned . If you see a flame 3 to 4 inches out of the slot or bigger, sounds like a pressure problem, you may have a bad appliance regulator, or maybe even the gas company’s regulator may have a problem.