Tuyển Cộng tác viên Hoc24 nhiệm kì 26 tại đây: https://forms.gle/dK3zGK3LHFrgvTkJ6
3333....3 x 6666...6
(20 c/s 3)(20 c/s 6)
= 3333...3 x 3 x 2222...2
(20 c/s 3) (20 c/s 2)
= 9999...9 x 2222....2
(20 c/s 9) (20 c/s 2)
= (1000...0 - 1) x 2222....2
(20 c/s 0) (20 c/s 2)
= 1000...0 x 2222...2 - 2222....2
(20 c/s 0) (20 c/s 2) (20 c/s 2)
= 2222....2000...0 - 2222...2
(20 c/s 2) (20 c/s 0)(20 c/s 2)
= 222...217...7778
(19 c/s 2) (19 c/s 7)
tinh nhanh : 33...3 . 66..6(moi so co 50 chu so)
Cau 3:Giai thich tai sao :
a/so co 4 chu so xyxy khi chia cho so 2 chu so xy lai co thuong la 101.
b/so co 6 chu so xyvxyv khi chia so co 3 chu so xyv lai co thuong la 1001
So hs khoi 6 cua 1 truong thcs khi xep hang 12,hang 20 deu du 7 hs.Tinh so hs khoi lop 6 cua truong do biet so hs la mot so tu nhien co 3 chu so lon hon 750
Co bao nhieu so co 5 chu so ma so do chia het cho 3 ,dong thoi co it nhat 1 chu so 6
co bao nhieu so co 3 chu so ma ton cac chu so cua no = 6
so tu nhien lon nhat co ba chu so 6, 3, 0 moi chu so viet mot lan la so :
so tu nhien nho nhat co ba chu so 6, 3 ,0 moi chu so viet mot lan la so :
hieu giua chung la :
.......... - ........... = ..........
tim so tu nhien co 3 chu so ,biet rang so do gap 20 lan tong cac chu so cua no
1 .Viet tap hop A gom cac so chan co 3 chu so va co tong cac chu so bang 5.
2 .Viet tap hop B gom cac so le co ba chu so va co tich cac chu so bang 6.
co bao nhieu chu so co 3 chu so ma tong chung bang 6
