Adding A Series of Numbers
Formulas :
( __ + __ ) ÷ 2 × ( __ − __ + 1)
Example :
(20 + ... + 35)
(20 + 35) ÷ 2 × (35 − 20 + 1)
55 ÷ 2 × 16
So, (20 + ... + 35) = 440
Formulas :
( __ + __ ) ÷ 2 × ( __ − __ + 1)
Example :
(20 + ... + 35)
(20 + 35) ÷ 2 × (35 − 20 + 1)
55 ÷ 2 × 16
So, (20 + ... + 35) = 440