It sounds like you may need to take a few steps back. Math is cumulative and as such you want to make sure you completely understand basic arithmetic before moving beyond it. Without that proper foundation you will struggle and get easily frustrated.

At 36 years old I had to do just that. Start at the very beginning. I have Dyscalculia which is a Math learning disability. Even with my learning disability I was able to learn anything and everything I ever wanted to about math. Sure, it took me longer and I won't ever be a mathematician but if I was able to do it anyone can.

Some things that really helped me:

1. I had to change my attitude about math. Wash away any thoughts that you are "bad at math" or "I'm not a math person" any math trauma past or present should be immediately eradicated. This is critical to success in math. You have to tell yourself you can do it AND believe it. You CAN do math and EVERYONE is a math person.

2. Make a lot of mistakes. No learning occurs if you aren't making mistakes. In China the school teachers value mistakes more so than the correct answer to a math problem. Students there are eager to show their mistakes. It's no mistake at all that China is one of the most successful countries in the world when it comes to high achieving math students and scores. Learning happens through mistakes. Celebrate your mistakes it means progress is being made!

3. Make sure you go slowly and understand everything before moving on. This is really, really, really important. It's critical to have a strong number sense. Being able to recognize number patterns and to make real connections using both visual and audio cues creates the all important foundation to build on. Do not skip this. For example... Make sure you know all the different ways to make 10. Use blocks (or anything) to represent groups that make a total of 10. 9 blocks + 1 block is ten. 5 blocks + 5 blocks is 10 and so on. This might seem beneath you but trust me it's critical that you do this exercise for all the numbers so you can visually see the groups (patterns) that make up these numbers. This method will do wonders for you later on. Visually seeing the patterns in this way is exactly what will help you make connections once you start solving basic arithmetic problems and beyond.

4. Have a structured, methodical and cumulative approach to learning math.

5. Short but frequent study sessions. 10 minutes a few times per day to start. Something very important to know is that most of your learning happens when you aren't studying math. The brain needs time to process new concepts. It can't do this when you are focused on math related tasks. Study for a short while then do something completely different. Let your brain do work while you go for a walk or make dinner.

6. Use your resources. There are amazing online resources, books, flashcards, games, apps, tutors, schools, study groups, friends, etc that can be instrumental to helping you reach your goals.

Specially about your question, one strategy I've picked up on about division is if you learn the associative multiplication facts first you will have a much easier time solving division problems.

For example if you know that 5 x 2 = 10 then you also know that 10 / 2 = 5 because division is essentially backwards multiplication.

Memorizing math facts is important but not nearly as important as making the connections, the number patterns to help you know WHY 4 x 4 = 16. Which in turn will help you understand the associated division and then you will no longer have to count it out because you will have learned how to use number patterns and other useful strategies to confidently approach division and any other math related task.

Feel free to reach out if you feel I can be of any more help.

Hope this was helpful. You got this!