Question

A= 1.2+2.3+3.4+.....+ 99.100 = ?

Answer 1

3A=1.2.3+2.3.3+3.4.3+...+99.100.3

3A=1.2.3+2.3.(4-1)+3.4.(5-2)+...+99.100.(101-98)

3A=1.2.3+2.3.4-1.2.3+3.4.5-2.3.4+...+99.100.101-98.99.100

3A=99.100.101

3A=999900

A=999900:3

A=333300

Answer 2

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