1. (2020一上·桐梓期末) 看谁算得又对又快

15-5=            2+5=            7-4=            8+7=

10-0=            8+6=            7+7=            6+9=

5-4+9=           9-5+7=           5+4-3=

10-6+3=          7-3+8=           8+9-2=