Union and intersection of intervals

[Michael76b]

Can anyone here help me understand how to do this? I’ve been reading and watching videos for hrs and still don’t understand this. I have to write the answer in interval notation

[mysonx3]

Do you understand what union and intersection mean? Do you know how to use interval notation?

I'm confused as to what you need to learn how to do

[bjcheung77]

For math, I usually recommend to view examples on YouTube. You need to review everything they say and examples they have, plus you also want to see if you can grab some workbooks at the local library. Practice makes perfect.

[MNomadic]

Think of union as "OR" and intersection as "AND"

Union means it's in at least 1 of the sets, so this set OR the other set(or even both).

Intersection means it must be included in all the sets, so this set AND the other set.

That's kind of a simple explanation... I think Khan would probably be able to explain better.

[davewill]

You might find it helpful to get used to translating back and forth between interval notation and plotting the sets on a number line with the endpoints either as closed or open circles depending on whether the endpoint is in the set. Once you're comfortable translating back and forth between interval notation and number lines, do a bunch of examples where you take two sets, plot them as number lines, figure out the union or intersection as a number line, then translate back to interval notation. Hopefully that will help you visualize what is occurring better.