Question

encontre a soma dos 70 primeiros numeros naturais impares

Answer 1

an=a1+(n-1).r
a70=1+(70-1).2
a70=1+69.2
a70=1+138
a70=139
sn=(a1+an).n/2
s70=(1+139).70/2
s70=140.70/2
s70=9800/2
s70=4900

Answer 2

1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41+43+45+47+49+51+53+55+57+59+61+63+65+67+69+71+73+75+77+79+81+83+85+87+89+91+93+95+97+99+101+103+105+107+109+111+113+115+117+119+121+123+125+127+129+131+133+135+137+139 = 4900.
Eu acho que é isso.