12.68-22.78÷3.4=12.68-6.7=5.98哦。谢谢，但是要是简便方法啊？12.68-22.78÷3.4=10+2.68-22.78÷3.4=34÷3.4+2.68-22.78÷3.4=34÷3.4-22.78÷3.4+2.68=11.22÷3.4+2.68=(10.2+1.02)÷3.4+2.68=3+0.3+2.68=5.98