4) 4la n=64
4 la n=4 la 3
=>n=3
5)a+(a+1)+(a+2)+(a+3)=62
4a+6=62
4a=62-6
4a=56
a=56:4
a=14
I numar=14
al II lea=15
al III lea=16
al IV lea=17
6)12379 rotunjit la sute=12400
7)a:7=10 rest 5
=>a=10x7+5
a=75
8)a(b+c)=3114
ab=1107
axc=?
a(b+c)=3114
ab+ac=3114
1107+ac=3114
ac=3114-1107
ac=2007
9)24x-1=47
24x=46
x=46/24
x=23/12=1,91(6)
10)(5la2-4la2):9=
25-16):9=
9:9=1
[12x35-12x24+12]=
factor comun 12
12(35-24+1)=
12x12=144
[9la2-2la4x5la9:(5la4)la2]:2=
[9la2-2la4x5la9:5la8]:2=
(81-16x5):2=
(81-80):2=1:2=0,5
