题目内容
306+19-95
(340-290)÷25
38×(63-24)
420÷30×352
230-180÷18
333-192-108
自己再出一道先减后加的算式,并算出来.
(340-290)÷25
38×(63-24)
420÷30×352
230-180÷18
333-192-108
自己再出一道先减后加的算式,并算出来.
分析:(1)先算加法,再算减法;
(2)先算减法,再算除法;
(3)先算减法,再算乘法;
(4)先算除法,再算乘法;
(5)先算除法,再算减法;
(6)利用减法的性质简算.
先减后加的算式:450-230+112.
(2)先算减法,再算除法;
(3)先算减法,再算乘法;
(4)先算除法,再算乘法;
(5)先算除法,再算减法;
(6)利用减法的性质简算.
先减后加的算式:450-230+112.
解答:解:(1)306+19-95
=325-95
=230;
(2)(340-290)÷25
=50÷25
=2;
(3)38×(63-24)
=38×39
=342;
(4)420÷30×352
=14×352
=4928;
(5)230-180÷18
=230-10
=220;
(6)333-192-108
=333-(192+108)
=333-300
=33.
先减后加的算式:
450-230+112
=220+112
=332.
=325-95
=230;
(2)(340-290)÷25
=50÷25
=2;
(3)38×(63-24)
=38×39
=342;
(4)420÷30×352
=14×352
=4928;
(5)230-180÷18
=230-10
=220;
(6)333-192-108
=333-(192+108)
=333-300
=33.
先减后加的算式:
450-230+112
=220+112
=332.
点评:混合运算的关键是,抓住运算顺序,正确按运算顺序计算即可.
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