题目内容
728+199．
解：728+199，
=728+（200-1），
=728+200-1，
=928-1，
=927．
分析：先把199分解成200-1，再使用加法结合律简算．
点评：本题使用凑整法，把接近整十、整百、整千的数字分解成整十、整百、整千与另一个数的和或差，然后再运用运算定律进行求解．
=728+（200-1），
=728+200-1，
=928-1，
=927．
分析：先把199分解成200-1，再使用加法结合律简算．
点评：本题使用凑整法，把接近整十、整百、整千的数字分解成整十、整百、整千与另一个数的和或差，然后再运用运算定律进行求解．
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