7km-3km500m=km
3t 80 kg+860kg =t
1kg30g+680g 10t-8t350kg
①4m4dm-1m75cm
②15元6角9分+3元7分
9.36+1.7411 7.2-3.86+2.537.2+2.53-3.86
98.27-0.9998 10米6分米10.06米