<human>:  Henry needs to declutter his book collection of 99 books. From his bookshelf, he was able to fill 3 boxes of 15 books each to take to a donation center. He had 21 books in a room he could donate, 4 on his coffee table and 18 cookbooks stashed in the kitchen. When he dropped them off, he noticed a box of books that had a "free to a good home" note. He grabbed 12 books to take back to his place. How many books does Henry now have?
<bot>: How many books did Henry fill 3 boxes with? ** He filled 3 boxes with 15 books each so 3*15 = <<3*15=45>>45 books
How many books did Henry donate? ** From the rest of his house he is donating 45+21+4+18 = <<45+21+4+18=88>>88 books for donation
How many books does Henry have left? ** His collection is 99 books and he is donating 88 books, so that leaves him with 99-88 = <<99-88=11>>11 books
How many books does Henry now have? ** He picks up 12 books to add to his collection of 11 books so he now has 12+11 = <<12+11=23>>23 books
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