calculati,folosind metoda factorului comun;
a) 3*7+3*15+3*13
b)33+117+33*15+33*113
c)201*327-201*307+201*23
d)217*407-217*397-217
e)1725*707+324*707-321*707
f)(111+222+333+444):111

Răspuns:

a) 105

b) 8085

c) 8643

d) 1953

e) 1221696

f) 10

Explicație pas cu pas:

a)

3 × 7 + 3 × 15 + 3 × 13 =

3 × (7 + 15 + 13) =

3 × 35 =

105

b)

33 × 117 + 33 × 15 + 33 × 113 =

33 × (117 + 15 + 113) =

33 × 245 =

8085

c)

201 × 327 - 201 × 307 + 201 × 23 =

201 × (327 - 307 + 23) =

201 × 43 =

8643

d)

217 × 407 - 217 × 397 - 217 =

217 × (407 - 397 - 1) =

217 × 9 =

1953

e)

1725 × 707 + 324 × 707 - 321 × 707 =

707 × (1725 + 324 - 321) =

707 × 1728 =

1221696

f)

(111 + 222 + 333 + 444) : 111 =

111 × (1 + 2 + 3 + 4) : 111 =

111 × 10 : 111 =

10

Răspuns:

Explicație pas cu pas:

a)     3(715+13)=3835=105 ;   b) gresit ;   c)  201(327-307+23)=201*350=70350 ;   d) 217(407-397-1)=217*9=1953 ;  e) 707(1725+324-321)=1221696 ;                            f) 111(1+2+3+4):111=10