问题
解答题
脱式计算.
6450-2600÷650×278
(512+2688÷56)×73
(9640-5230)÷(38+25)
答案
(1)6450-2600÷650×278
=6450-[4×(300-22)],
=6450-[4×300-4×22],
=6450-[1200-88],
=6450-1112,
=5338;
(2)(512+2688÷56)×73
=(512+48)×73,
=560×(70+3),
=560×70+560×3,
=39200+1680,
=40880;
(3)(9640-5230)÷(38+25)
=4410÷63,
=70.