解:(1)10.75-(2.4-0.86),
=10.75-1.54,
=9.21;
(2)9.61-4.38+0.35,
=5.23+0.35,
=5.58;
(3)3.87+4.92+1.13,
=(3.87+1.13)+4.92,
=5+4.92,
=9.92;
(4)46.24-8.66-1.34,
=46.24-(8.66+1.34),
=46.24-10,
=36.24;
(5)21.9-9.22-0.78+8.1,
=21.9-(9.22+0.78)+8.1,
=21.9-10+8.1,
=11.9+8.1,
=20;
(6)(745-25×16)÷15,
=(745-400)÷15,
=345÷15,
=23.
分析:(1)先算小括號(hào)里面的減法,再算小括號(hào)外面的減法;
(2)先算減法,再算加法;
(3)根據(jù)加法交換律和結(jié)合律進(jìn)行簡(jiǎn)算;
(4)46.24連續(xù)減去8.66與1.34,等于減去這8.66與1.34的和;
(5)21.9連續(xù)減去9.22與0.78,等于減去這9.22與0.78的和,然后再按照從左向右的順序進(jìn)行計(jì)算即可.
(6)先算小括號(hào)里面的乘法,再算小括號(hào)里面的減法,最后算除法.
點(diǎn)評(píng):四則運(yùn)算,先弄清運(yùn)算順序,然后再進(jìn)一步計(jì)算,能簡(jiǎn)算的要簡(jiǎn)算.