2.84÷2.5=（3-0.16）×0.4=1.2-0.064=1.136
2.84÷2.5简便方法用递等式计算=2.84/（1/4）=2.84x4=11.36
203.4+43.2÷2.5简便递等式203.4+43.2÷2.5=203.4+17.28=220.68.
