seems more work then needs be but 7+5= 12 and she originally had 23. so the equation of adding the 7+5 would just be adding up the ones removed together then adding the -23 to the equation is how many Amy had to begin with. so it would be <u><em>23-7+5 </em></u>= 12. others dont seem right since when you add () to an equation that means your multiplying and you wouldn't be multiplying here and for D to be right it needs to be switched around or you'd end up with a - number and she wouldn't have a - number of blocks. just divide up a problem if need be and break it down to smaller parts to make it easier to deal with.
