If you have kids under 20, there's a fair chance your kid has played Minecraft before. It's been a huge hit in my house and among our homeschool friends. Some have likened it to computerized Legos, in the sense that you collect blocks and use them to build things. You also craft tools, weapons, food, paintings, armor, etc. (If you choose, you can also fight zombies, spiders, and other nasties.)
My son and I have used exclusively Minecraft examples to learn simple multiplication and division. If your child plays Minecraft and you don't, you can use the Minecraft Wiki to come up with a few problems, if you want to try this.
For instance: You need to make 3 wooden doors. How many wooden planks will it take? A Minecraft player knows it takes 6 planks to make 1 door, so the answer is 3 x 6 = 18.
If you already have a set amount of material in your inventory -- 16 wooden planks, let's say -- you might want to know how many storage chests you can craft. Since it takes 8 planks to make a chest, the answer is 16 / 8 = 2.
It goes without saying that these problems are much more interesting than the absurdly stupid examples used in many workbooks, which both my kids have always found rather insulting.
Many of the problems I've used are far more complicated and require multiple steps. For example, say you want to make 40 pieces of wooden fence. This is a realistic goal if you're going to raise livestock. Well, you make fencing out of sticks, 6 sticks = 2 fences. And you make sticks out of planks, 2 planks = 4 sticks. And for each log chopped from a tree you get 4 wooden planks. So how many logs do you need?
40 fence pieces / 2 = 20 pairs of fence; 20 x 6 = 120 sticks; 120 / 4 = 30 pairs of planks, i.e. 2 x 30 = 60 planks; 60 planks / 4 = 15 logs.
The difficulty is actually that my kids, who have played an ungodly number of hours of Minecraft, will do a lot of this math without thinking-- or I should say without being able to articulate what it was they did. So in some ways the long, complicated problems are easier because they're more willing to break it down into steps and recognize the multiplying and dividing that's occuring.
My daughter is 12, and is working on fractions and proportions and percentages. That's fairly easy to do too. One pile of glowstone dust is 1/4 of a block of glowstone. A gold ingot is 1/9 of a gold block. Bronze (available in one of the mods) is made from 3 parts copper to 1 part tin. Bronze armor is 30% more durable than iron armor; what does that mean? The Efficiency enchantment increases pick-axe speed by 50%, while Efficiency II increases it by 100% -- what does a 100% increase mean?
Of course, I am really only re-discovering what DnD players knew decades back: that gaming involves a lot of math. And if it's math that really grabs your attention, you learn it faster and remember it better. And for kids, this is as "in context" as it gets, when it involves one of their favorite games.