计算:
①5.24+7.9+4.76
②25×37×4
③5.12-1.47-2.53
④156×101-156⑤450÷5÷9⑥52×23+48×23⑦4.5+3.15-4.5+3.15.
网友回答
解:①5.24+7.9+4.76,
=5.24+4.76+7.9,
=10+7.9,
=17.9;
②25×37×4,
=25×4×37,
=100×37,
=3700;
③5.12-1.47-2.53,
=5.12-(1.47+2.53),
=5.12-4,
=1.12;
④156×101-156,
=156×(101-1),
=156×100,
=15600;
⑤450÷5÷9,
=450÷(5×9),
=450÷45,
=10;
⑥52×23+48×23,
=(52+48)×23,
=100×23,
=2300;
⑦4.5+3.15-4.5+3.15,
=(4.5-4.5)+(3.15+3.15),
=0+6.3,
=6.3.
解析分析:①运用加法交换律简算;
②运用乘法交换律简算;
③根据连续减去两个数等于减去这两个数的和简算;
④⑥运用乘法分配律简算;
⑤根据连续除以两个数,等于除以这两个数的积简算;
⑦运用加法交换律和结合律简算.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.