Question

(2+4+6+ ... +100)/51 = ?

Answer 1

(2+4+6+...+100)/51=2(1+2+3+....+50)/51=2(50*51/2)/51=50*51/51=50

Am aplicat formula lui Gauss.

Answer 2

$(2 + 4 + 6 + ... + 100) \div 51 =$

îl dăm pe 2 factor comun ,apoi putem folosi formula lui Gauss

$= 2(1+ 2+ 3 + ... + 50) \div 51 = \\ = 2 \times \frac{50 \times 51}{2} \div 51 =$

se simplifica 2 cu 2

$= 50 \times 51 \div 51 = \huge50$

EXPLICATIE :

formula lui Gauss este:

1+2+3+...+n= n•(n+1)/2