Question

1+2+3+...+20/2+4+6+...+40

Answer 1

Răspuns:

Explicație pas cu pas:

( 1+2+3+......+20) / (2+4+6+....+40) =1/2

= ( 1+2+3+....+20)/2(1+2+3+....+20) =

= 1/2

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Sau efectuand calculele:

= (20×21:2) / (2× 20×21:2) =

= (10×21)/(20×21) =

= 210/420 =

=(210:210)/(420:210) =

= 1/2

Answer 2

Răspuns:

1+2+3+4....+20=

nr de nr= (20-1)/1+1=20

suma=20x21/2=210

4+6+...+40=

36/2+1=nr de nr =19

suma= nr de nr x ultimul nr+primul/2

suma=19x44/2=19x22=418

suma totala=210+418=628

Explicație pas cu pas: