bai 1
cho so A = 123456 ... 50515253 bang cach viet lien tiep cac so tu nhien tu 1 den 53
a) hoi A co bao nhieu chu so tat ca
b) chu so 2 xuat hien bao nhieu lan
c) chu so thu 50 la chu so nao
d) tinh tong cac chu so cua A
bai 2
viet lien tiep cac so tu nhien tu 5 den 90 ta duoc so B = 5678910 .... 888990
a)hoi B co bao nhieu chu so
b) chu so 2 xuat hien bao nhieu lan
c) chu so thu 50 la chu so nao
d) tinh tong cac chu so cua B
ban nao tra loi ho minh nhe minh tich ngay lap tuc
Viet lien tiep cac so tu nhien le thanh day 13579111315.....
a) Chu so thu 100 cua day la chu so nao ?
b) Chu so 1 cua so 2013 la chu so thu bao nhieu cua day ?
Ghi ro day du cach lam to cho 1 tich nhung phai that nhanh len
Cho so: 1234567891011............................hoi chu so thu 2017 cua so nay la so nao???
viet cac so tu nhien lien tiep tu 1 den 100 tu trai sang phai thanh day :
a, day tren co bao nhieu chu so ?
b, chu so thu 1000 ke tu trai sang phai la nhung chu so nao ; la chu so cua so nao
viet so tu nhien N =12345678910111213141516...70 ,
a)so N co bn chu so
,b) cs hang don vi cua so 53 dung hang thu may (ke tu trai sang phai moi cs 1 hang),
c) cs viet o hang thu 120 la cs nao?cs do cua so tn nao
So thu 1000 cua day so 7;12;17;22;27...la so nao ?
So thu 1992 va 38264thuocday so da cho ko?neu co thi la so thu may cua day
cho dãy số tự nhiên liên tiếp khác 0: 2,4,6,8,......,10000
a, nếu viết liên tiế dãy số thì tya có dãy sô : a= 2468...10000 vay a co bao nhieu chu so
b chu so thu 2020 thuoc chu so nao thuoc so nao
c, chu so thu 2025 2026 thuoc so nao la chu so nao
cho day so :2,4,6,8 .....,2480
a. day so tren co bao nhieu so hang
b. tim so hang thu 2015 cua day
c.tinh tong 2015 so hang dau tien cua day
d.chu so thu 2015 cua day la chu so nao
cho day so 1,1;2,2;3,3;.....99,0. hoi so hang thu 50 cua day so la so nao