what is the sum of first 45 natural numbers?
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Answered by
0
Let Sn =(1 + 2 + 3 + ... + 45). This is an A.P. in which a =1, d =1, n = 45.
Sn =n[2a + (n - 1)d]=45x [2 x 1 + (45 - 1) x 1]=45x 46= (45 x 23)222
= 45 x (20 + 3)
= 45 x 20 + 45 x 3
= 900 + 135
= 1035.
Shorcut Method:
Sn =n(n + 1)=45(45 + 1)= 1035.22
HOPE IT HELPS ......
Sn =n[2a + (n - 1)d]=45x [2 x 1 + (45 - 1) x 1]=45x 46= (45 x 23)222
= 45 x (20 + 3)
= 45 x 20 + 45 x 3
= 900 + 135
= 1035.
Shorcut Method:
Sn =n(n + 1)=45(45 + 1)= 1035.22
HOPE IT HELPS ......
Answered by
1
1+2+3+4+5+6+7+8+9+10=55
11+12+13+14+15+16+17+18+19+20=155
21+22+23+24+25+26+27+28+29+30=255
31+32+33+34+35+36+37+38+39+40=355
41+42+43+44+45=215
55 + 155+ 255+ 355+ 215 = 1035.
11+12+13+14+15+16+17+18+19+20=155
21+22+23+24+25+26+27+28+29+30=255
31+32+33+34+35+36+37+38+39+40=355
41+42+43+44+45=215
55 + 155+ 255+ 355+ 215 = 1035.
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