Question

Ajutati-ma la exercitiile 19 si 20

19.1+3+5+....99=

a)50500. b)25250. c)49995. d)50250

20.5+10+15+20+.....500=

a)2450. b)2500. c)5000

Answer 1

1+3+5+....99=

de la 0 la 100 sunt 50 nr. impare

(1+99)×50:2=

100×50:2=

5000:2=2500

Era Suma lui Gauss.

Sper că te-am ajutat!!

Answer 2

19).

[(99-1):2+1]:2×100=

=50:2×100=

=25×100=

=2500

20).

[(500-5):5+1]:2×505=

=100:2×505=

=50500:2=

=25250