142)
11 t+5 m=43 |×7
3 t+7 m=23 |×5
77 t+35 m=301
15 t+35 m=115
77 t-15 t=301-115=186
62 t=186
t=186:62=3 lei
Înlocuim
3×11+5 m=43
33+5 m=43
5 m=43-33=10
m=10:5=2 lei
143)
48 m=>4800 cm
25 m=>2500 cm
4800×2500=12000000 cm2
40×40=1600 cm2
12000000:1600=7500 placi
7500:12=625 pachete
