二年级数学上册口算能力竞赛题

35 + 10 =80 – 20 =65 – 50 =23 + 3 =16 + 30 =35 + 40 =16 + 8 =21 + 8 =85 – 9 =23 + 30 =56 + 9 =67 – 4