1. (2022一下·甘南期中) 口算

16-8=            40+2=             15-6+7=             7+10-9=

78-8=            16-9=              17-9+8=             12-5-4=

12-9=            17-8=              14-4-2=              3+9-5=

60+7=            20+9=             87-7=                55-50=