371*10=3710, 371*100=37100,371*1000=371000, 84*1000:10=8400,35*1000:100=350, 47*100:100=47, 917-828=89, 218-159=59, 58+642+87=787,89+372+28=489, 900-638=262, 604-187=417,199*5=995, 68*9=612.