用简便方法计算. 569+68+132+31 125×88 2300-165-35 125×(8+4) 3200÷25÷4 156×l0l-156.
(1)569+68+132+31, =(569+31)+(68+132), =600+200, =800; (2)125×88, =(125×8)×11, =1000×11, =11000; (3)2300-165-35, =2300-(165+35), =2300-200, =2100; (4)125×(8+4), =125×8+125×4, =1000+500, =1500; (5)3200÷25÷4, =3200÷(25×4), =3200÷100, =32; (6)156×l0l-156, =156×(101-1), =156×100, =15600. |