用英语表达所给算试

8 sums/adds/plus 9 is/equal to 17

50 substracts/minus 19 is/equal to 31
只举两个，以此类推。

eight plus nine equals seventeen
sixteen plus eighteen equals thirty-four
twenty-fight plus twenty-two equals forty-seven
fifty minus ninteen equals thirty-one
seventy minus thirty-three equals forty-two