Addition in Daily Life

In the past half-year to a year, SpiderGirl has not made any particular advances in her adding and subtracting.  I have shown her a bit of grouping and borrowing.  Mostly, she has relied on the abacus for multi-digit addition and subtraction.  Since SpiderGirl has not seemed to find such computation easy, I figured that maybe she wasn't ready for this aspect of math and I didn't push it.

Wasn't I surprised when, yesterday, as I was keeping a tally of our bill as we shopped for groceries, SpiderGirl whipped out her notebook and started doing the addition and keeping track for me.  Adding in whole dollars, she added in the ones and tens places; she carried to the next place value (though we have never used that term); she did it all in her head and with about 90% accuracy.  

Wouldn't you know that it would be money that inspired her to practice her computation!  At the same time, SpiderGirl has been trying to add coin values in her head for a long time, although once she gets past 50 cents, she starts making errors.  I think having the visual focus of a notebook in front of her probably helped too.