Question

11、計算：3.68×15.7-31.4+15.7×0.32=

31.4

．

Answer 1

分析：首先3.68×15.7+15.7×0.32通過因式分解提取公因數(shù)15.7，使3.68+0.32結(jié)果為整數(shù)4．再-31.4計算．

解答：解：3.68×15.7-31.4+15.7×0.32
=15.7×（3.68+0.32）-31.4
=15.7×4-31.4
=31.4×2-31.4
=31.4
故答案為31.4

點評：本題考查因式分解的應(yīng)用．解決本題通過因式分解提取公因數(shù)15.7，從而使3.68+0.32結(jié)果為整數(shù)4，大大降低了計算的數(shù)據(jù)量．