Question

29. Efectuati: a) (1+2+3+...+2014):2015; b) (1+2+3+4+...+200):201; c) (2+4+6+ ... +400): [(4+8+ ... +100):13]; d) (5+10+15+ ... +525):(1+2+3+...+105). Plss ajutor​

Answer 1

Răspuns:

a) 2014×2015:2:2015=2014:2×1=1007×1=1007

b) 200×201:2:201=200:2×1=100

c) 2(1+2+3....+200):[4(1+2+....+25):13]=2(200×201:2):[4(25×26:2):13]=2×20100:(4×325):13=40200:1300:13=40200:100=402

d) 5(1+2+3+...105):(1+2+3+...+105)=5×1=5