Question

23.Rotunjiti la zeci de mii produsul 100 n in urmatoarele cazuri:
a) n=71+72+73+...+123
b)n=87+88+89+...+157

Answer 1

a)n=71+72+73+...+123
123-71+1=53 numere
52:2=26 grupe
71+123+72+122+....97=194*26+97=5044+97=5141
5141x100=514100
rotunjit la zeci de mii  510000 (prin lipsa)

b)n=87+88+89+...+157
157-87+1=71
70:2=35
87+157+88+156+.....+122=244*35+122=8540+122=8662

8662x100=866200
rotunjit la zeci de mii  870000    (prin adaos)