Question

A=20+21+22+23+24+25+26+37+28+29+30

Answer 1

A=20+30)+(21+29)+(28+22)+(27+23)+(26+24)+25

=>A=50+50+50+50+50+25

=>A=250+25

=>A=275

Answer 2

A=20+21+22+23+24+25+26+37+28+29+30

= (20+30)+(21+29)+(22+28)+(23+27)+(24+26)+25

=  50 + 50 + 50 + 50 + 50 + 25

= 100 + 50 + 50 + 50 + 25

= 150 + 50 + 50 + 25

= 200 + 50 +25

= 250 + 25

 A = 275

Answer 3

123456789;10

Answer 4

a=20+21+22+23+24+25+26+27+28+29+30

a=[20+30]+[21+29]+[22+28]+[23+27]+[24+26]+25

a=50+50+50+50+50+25

a=275