Question

tính giá trị : 1+2+ 3+...+100+101+100+...+3+2+1=

 

Answer 1

1 + 2 + ... + 100 + 101 + 100 + ... + 3 + 2 + 1

= 2 × (1 + 2 + 3 + ... + 100) + 101

= 2 × 100 × 101 : 2 + 101

= 10100 + 101

= 10201

Answer 2

1 + 2 + ... + 100 + 101 + 100 + ... + 3 + 2 + 1

= 2 × (1 + 2 + 3 + ... + 100) + 101

= 2 × 100 × 101 : 2 + 101

= 10100 + 101

= 10201

Answer 3