Ta có: \(\overline{cba}-\overline{abc}=\left(100\times c+10\times b+a\right)-\left(100\times a+10\times b+c\right)\)
\(=100\times c+10\times b+a-100\times a-10\times b-c\)
\(=99\times c-99\times a=99\times\left(c-a\right)=99\times4=396\)
Ta có: \(\overline{cba}-\overline{abc}=\left(100\times c+10\times b+a\right)-\left(100\times a+10\times b+c\right)\)
\(=100\times c+10\times b+a-100\times a-10\times b-c\)
\(=99\times c-99\times a=99\times\left(c-a\right)=99\times4=396\)
Khi cong mot so tu nhien co 4 chu so voi mot so tu nhien co 5 chu so,mot ban da dat tinh nham de cac chu so cua so co 4 chu so lech sang ben trai 1 hang va thang hang voi cac chu so cua so co 5 chu so.Vi vay ket qua thu duoc tang them 11106 don vi.Hoi:a.Tim ket qua dung cua phep cong biet so co 5 chu so la 12345.b.Tim so co 5 chu so do biet ket qua sai la 55550
khong lam phep tinh ,hay cho biet ket qua cua moi phep tinh sau co tan bang chu so nao ?giai thich tai sao?
a.2*4*6*8...*96*98*5
b.5*15*25*...*2025
c.59*69*79*89-21*41*61*81
d.4*14*24*...*2024
a) cho 20 so chan lien tiep biet rang so chung binh cong la 101 tim so lon nhat
b) tich 19 x 29 x 39 x ..... x ket qua co chu so tan cung la may
c) tinh tong cua 30 so le lien tiep tu 123 tro di . tong cua cac so do la
tim so co 3 chu so abc biet rang a la so du cua abc chia 2,b la so du cua abc chia 3,c la so du cua abc chia 4.Biet rang cac so co the trung nhau.
Tim 2 so co hiểu bang 516 biet rang nếu lay so lon chia cho so be thi duoc thuong bang 4.
Tim hai so biet ti so cua chung bang 4/7 va nếu lay so lon tru đi so be thi duoc ket qua bang 360.
Ca 3 nguoi tho lam cong duoc 270000 dong. Nguoi thu nhat duoc 1/3 so Tiền. Nguoi thu ba duoc 2/5 so tien. Tinh tien nguoi thu ba.
Cho 4 chu so 0,3,8,9. Viet duoc bao nhieu so tu nhiên co 4 chu so khác nhau tu 4 chu so da cho.
Lop 5A co 1/2 so hoc sinh nữ bang 1/5 so hoc sinh nam. Biet so hoc sinh nữ kem so hoc sinh nam la 15 ban . Tinh hoc sinh nam va hoc sinh nữ.
khi thuc hien phep nhan 2 thua so, mot ban da viet nham 2 chu so cuoi cung cua thua so thu 1 la 35 thanh 53 nen co ket qua la 22197.tim 2 thua so da cho, biet rang tich dung cua chung la 21315
khi lay mot so tu nhien tru di mot so co 2 chu so, mot ban dat tinh nhu sau: chu so hang don vi cua so tru dat thang cot voi chu so hang chuc cua so bi tru va chu so hang chuc cua so tru dat thang cot voi chu so hang tram cua so bi tru va ket qua la 1154. Tim 2 so biet hieu dung la 432
Ket qua cua day tinh:1*2*3*4*5*6*7+64:8 co tan cung la chu so nao?
lan thuc hien 1 phep nhan do viet nham chu so hang don vi cua thua so thu 2 tu 2 thanh 8 nen da duoc ket qua la 2034 ma dang le phai la 1356 em hay tim cac thua so ban dau cua phep tinh do