Question

36. Dați factor comun, pentru a calcula mai simplu:
a) 209.43+209.57;
b) 198.7-6.198;
c) 4+8+12+ ... +148;
d) 2009. 92-92.9;
e) 877.2001 - 877;
f) 365+ 365.17-365.18;
g) 11+22+33+...+99;
h) 27.37-37.17.​

Answer 1

Explicație pas cu pas:

a)209(43+57)=209×100=20900

b)198(7-6)=198×1=198

c)(148+4)×38÷2=152×19=2888

d)92×(2009+9)=92×2018=185656

e)877×2000=1.754.000

f)365×18-356×18=0

g)11+99+22+88+33+77+......+55=110+110+110+110+55=440+55=495

h)37(27-17)=37×10=370

Answer 2

Răspuns:

Explicație pas cu pas:

a) 209·43+209·57=209(43+57)=209·100=20900

b) 198·7-6·198=198(7-6)=198

c) 4+8+12+ ... +148=4(1+2+3+....+37)=4·37·38/2=2·37·38=2812

d) 2009·92-92·9=92(1009-9)=92·1000=92000

e) 877·2001 - 877=877(2001-1)=877·2000=1754000

f) 365+ 365·17-365·18=365(1+17-18)=0

g) 11+22+33+...+99=11(1+2+3+....+9)=11·9·10/2=11·45=495

h) 27·37-37·17=37(27-17)=37·10=370​