Question

Efectuati operatii scriind rezultatul sub forma unei fractii ireductibile
A=4\15+3/20
B=5/24+1/12+3/8
C=7/30-3/20
D=8/15-9/20
E=8/21+4/35
F=7/6-3/4-1/12

Answer 1

a = 4/15 + 3/20 = (16+9)/60 = 25/60 = 5/12

b = 5/24+1/12+3/8 = (5+2+9)/24 = 16/24 = 2/3

c = 7/30-3/20 = (14-9)/60 = 5/60 =1/12

d = 8/15-9/20 = (32-27)/60=5/60 = 1/12

e = 8/21+4/35 =  (40+12)/105 = 52/105

f = 7/6 - 3/4 - 1/12 = (14-9-1)/12 = 4/12 = 1/3

Answer 2

A = 4/15 + 3/20 =16/60 + 9/60 = 25/60 = 5/12
cmmmc al numerelor ( 15, 20) = 2²x3x5=60
→ amplific cu 4 prima fractie si cu 3 a doua fractie
→ simplific fractia 25 / 60 cu 5 = 5/12

B = 5/24+1/12+3/8 = 5/24+2/24+9/24 = 16/24 = 2/3
cmmmc al numerelor ( 24, 12,8 ) = 2³×3= 24

C= 7/30-3/20 = 14/60-9/60 = 5/60 =1/12
cmmmc al numerelor ( 30, 20) = 2²×3×5=60

D = 8/15-9/20 = 32/60-27/60 = 5/60 = 1/12
cmmmc al numerelor ( 15, 20) = 2²×3×5


E = 8/21+4/35 =  40/105 +12/105 = 52/105
cmmmc al numerelor ( 21,35) = 3×5×7=105

F= 7/6 - 3/4 - 1/12 = 14/12 - 9/12 - 1/12 = 4/12 = 1/3
cmmmc al numerelor (6,4,12) =12