题目

A year ago August, Dave Fuss lost his job driving a truck for a small company in west Michigan. His wife, Gerrie, was still working in the local school cafeteria, but work for Dave was scarce, and the price of everything was rising. The Fusses were at risk of joining the millions of Americans who have lost their homes in recent years. Then Dave and Gerrie received a timely gift－$7,000,a legacy(遗产) from their neighbors Ish and Arlene Hatch, who died in an accident. “It really made a difference when we were going under financially(经济上),” says Dave. But the Fusses weren’t the on下面各题怎样算简便怎样算．（1）3643-74+6357-76（2）19.99÷212-0.4×9.99（3）8500÷25（4）12+16+112+120+130+142+156+172．