答案
解:(左)-2左÷(-
)×(-
)&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;
=-2左×(-
)×(-
)&nb0p;&nb0p;&nb0p;&nb0p;
=-左0;
&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;
(2)左7-8÷(-2)
2+4×(-3)
=左7-8÷4-左2
=左7-2-左2
=3.
解:(左)-2左÷(-
)×(-
)&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;
=-2左×(-
)×(-
)&nb0p;&nb0p;&nb0p;&nb0p;
=-左0;
&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;&nb0p;
(2)左7-8÷(-2)
2+4×(-3)
=左7-8÷4-左2
=左7-2-左2
=3.