Răspuns:
1. 12 13 14 15 16 17 18 19 - 8 numere
23 24 24 26 27 28 29 - 7 numere
34 35 36 37 38 39 - 6 numere
45 46 47 48 49 - 5 numere
56 57 58 59 - 4 numere
67 68 69 - 3 numere
78 79 - 2 numere
89 - 1 numar
1+2+3+4+5+6+7+8=8(8+1)/2=72/2=36 numere
2. 32:16+{76-2[(20+4*5):5]-2*6}=
2+{76-2[(20+20):5]-12}=
2+[76-2(40:5)-12]=
2+(76-2*8-12)=
2+(76-16-12)=
2+(60-12)=
2+48=50
3.a:6=c r, c=r, r<6 r={1,2,3,4,5}
a=6*c+r
a=6*1+1=7
a=6*2+2=14
a=6*3+3=21
a=6*4+4=28
a=6*5+5=35
a={7,14,21,28,35}
4. [(81-16*5):1+5]*4=(1:1+5)*4=6*4=24
5. 10*10=100
11*11=121
12*12=144
13*13=169
14*14=196
15*15=225
16*16=256
17*17=289
18*18=324
19*19=361
20*20=400
21*21=441
22*22=484
23*23=529
24*24=576
25*25=625
26*26=676
28*28=784
29*29=841
30*30=900
31*31=961
6.
770 si 775
7. 8m=?
7m dantela..... 280 lei
280:7=40 lei costa 1 m de dantela
40*8=320 lei ( atat costa 8 m dantela)
