Sometime last year I picked up a 100-bead style abacus at a second-hand sale. It’s wooden and sturdy–the tag says IKEA. Irresistible to touch. Fun to arrange into patterns.
Asking around about how to use it finally directed me to RightStart Math. A little perusing of their website and I figured out the secret was the way the beads are divided in fives. I taught the kids their rhyme about numbers from six to ten (six is five and one; seven is five and two, etc.). You can also demonstrate with fingers, which we did as well. With those visualizations in place, you can learn addition and subtraction by relating them to fives and tens–which unlocks all the addition facts. D1 caught on quickly: pondering how many children she would have if she had six girls and five boys, she realized it would be one more than ten ("five and five").
The abacus also allowed them to easily count and visualize numbers up to one hundred. They liked watching me count and demonstrating large numbers on it themselves. One of their favorite random things to do is to announce how old they are: "I’m 54!" "I’m 72!" Now they can illustrate these numbers on the abacus. I really like this even better than base10 style blocks–it’s neater and helps more with visualizations.
I’m also impressed with the math games that RightStart uses for review. I don’t think we need a curriculum yet, but when we do, RightStart is going to be at the top of my list. Right now playing "War" and "Go Fish" are pretty good math exercises. D1 will probably be ready to play two-card War soon, where you add the two cards together and the highest sum wins. D2 understands the larger number concept, but still has trouble with the losing concept. He announced his own rules to DOB: "Let’s play it so that whatever card I play, it wins."
The other day we were riding in the car and D2 announced to DOB that we had seen one workerwoman and two worker men, which made three worker persons. This set us off adding other disparate groups: "Two boys and one girl is three kids." "Two apples and one orange is three fruits." "Two buckles and one car seat are three things around you in the car." We kept this up all the way to the chiropractor.