I don't typically teach my kids things in a traditional way. We unschool, so things come up as we move through our life and we learn about them as they happen. Because I was a teacher, way back when, I have a few tricks up my sleeve, but mostly I follow their lead and try to get creative when they ask for something specific.
Lately, we've been playing tons of games. One of my favorite math games is called Salute. It is a simple card game that practices addition and subtraction facts. It can be used for multiplication and division as well. I worked with a principal many years ago who taught this to me. All you need are three people and a deck of cards. I use what I call leftover decks. You know all those decks of cards that are missing a few? Don't throw them away. They come in very handy. Depending upon the skill level of the children, I sort the deck, pulling out all face cards and higher numbers, if necessary.
Once you have your deck of digits, deal them to two players (called flippers). The third player will play, but will not need any cards. The three players sit in a triangle. The two players with cards begin by each flipping over their top card and holding it to their foreheads so that the other two players can see them. It is important that they not look at their own cards, only the card of the other card flipper. The two flippers should now have cards on their foreheads. The third player adds up the two digits and calls out the sum. The two flippers now subtract the number they can see (the flipper sitting opposite them) from the sum to get the number shown on their own card. They then call out their number.
Players can take turns being flippers and non-flippers to practice both subtraction and addition. It's fun, fast and a great way to play around with math.