Some of this may be rusty, but this help will refresh these ideas. We strongly suggest doodling number lines for a few days. Everyone needs to doodle, you need to practice, clearly doodling a few number lines will help you see the structure in counting by 2s and 5s.
These rewarding dings will help you practice multiplication and division. We particularly love the “Factor” game because it emphasizes how multiplication and division are related.
If it’s possible, practice the above tool until you can quickly and accurately remember the facts up to 10×10.
This two-digit multiplication tool will help you see why we “carry tens” and how you can solve any multi-digit multiplication.
One last thing. averages help us fine the middle of numbers. We add up all the values and divide by the number of values. The average will always be in the middle (it’s easy to miscount the number of values). Here’s a classic 3-minute or less video about finding mean (which is the average), median and mode.