cho day so 5, 10, 15, 20, ...tim so hang thu 125 cua day so do
cho day so 53,56,59,62,65,...tim so hang thu 1010 cua day so
Cho day so 53 ; 56 ; 59 ;62 ; 65 ; ........ Tim so hang thu 1010 cua day.
Tim so hang thu 2015 cua day so 3, 6,9,12...
Cho mot phet cong cong co so hang thu nhat hon so hang thu hai la 15 don vi .Biet tong cua so hang thu nhat so hang thu hai va tong bang 682. Tim so hang thu hai cua tong
Bai 1: cho day so 1,5,9,13,...
a) chu so thu 135 la chu so nao
b) tinh tong 200 so hang dau tien cua day
bai 2: 1/3,11/3,7,31/3,...
a) xac dinh so hang thu 2009 cua day da cho
b) trong 2009 so hang dau tien cua day co ? so tu nhien tinh tong tat ca cac so tu nhien do
tim so hang thu 99 cua day so1;6;15;28;....;120;153 .ai thong minh giai giup cai minh phai nop gap
1 +1+1+2+2+2+3+3+3+ ... +n .
tim tong biet n la so hang thu 216 cua day .
Cho day so:5,21,53,101,165.....
A.So 23765 la so hang thu may cua day ?
B.So hang thu 87cua day la so nao ?