Question

Вычислите удобным способом:

67+24

48+15

26+39+9

19+28+17+16+15

15+28+25+10+12

Answer 1

1)91
2)63
3)74
4)95
5)90

Answer 2

67+24 = 91
48+15 = 63
26+39+9 = 74
19+28+17+16+15 = ((17+15)+28)+16 + 19 = 32 = 28+32 + 35 =  60 + 35 = 95
15+28+25+10+12 = (15 + 25 ) + (28+12)  +10 = 40 + 40 + 10 = 90