B=1.3+5.7+....+97.101
B=1.3.(5+1)+3.5.(7-1)+......+97.99.(101-95)
B=1.3.5+1.3+3.5.7-1.3.5+....+97.99.101-97.99.95
B=1.3.5+3+3.5.7-1.3.5+.....+97.99.101-97.99.95
B=3+97.99.101
B=\(\dfrac{1+97.33.101}{2}\)
B=161651
Vậy B=161651
NHớ tick cho mình nha!!!!!!!!