Ta thấy trong 3 số thì số B là nhỏ nhất

B kém A 10 lần

B kém C 100 lần 

Tổng A+B+ C = 100 x B+ B + 10 x B = 111 x B = 221,778

B= 1,998 nên số A là 19,98

số C là: 199,8

100000000000000000/:

♤♤♤♤♤♡♡◇♡♡◇♧♧♡♡

19.98 đúng100%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

B kém A 10 lần

B kém C 100 lần 

A 10 phần ; C 100 phần ; B 1 phần

tổng số phần bằng nhau : 100 + 10 + 1 = 111 phần

số thập phân A là : 221,778 : 111 x 10 = 19,98

B kém A 10 lần

B kém C 100 lần 

A 10 phần ; C 100 phần ; B 1 phần

tổng số phần bằng nhau : 100 + 10 + 1 = 111 phần

số thập phân A là : 221,778 : 111 x 10 = 19,98

Bước 1: Đặt các biểu thức toán học

• Gọi A là số thập phân cần tìm.
• Khi chuyển dấu phẩy sang trái một hàng, ta được B = A ÷ 10.
• Khi chuyển dấu phẩy sang phải một hàng, ta được C = A × 10.
• Tổng của ba số được cho:
  [ A + B + C = 221,778 ]

Bước 2: Biến đổi phương trình

Thay B và C vào phương trình:
[ A + \frac{A}{10} + 10A = 221,778 ]

Bước 3: Quy đồng mẫu số và thu gọn biểu thức

Đưa về mẫu số chung là 10:
[ \frac{10A}{10} + \frac{A}{10} + \frac{100A}{10} = 221,778 ]

[ \frac{111A}{10} = 221,778 ]

Bước 4: Giải A

Nhân hai vế với 10:
[ 111A = 2217,78 ]

Chia hai vế cho 111:
[ A = \frac{2217,78}{111} = 19,98 ]

Kết quả

Vậy số thập phân A = 19,98.

Vì nếu chuyển dấu phẩy của nó sang bên trái 1 hàng thì số đó giảm đi 10 lần

Và nếu chuyển chuyển dấu phẩy của nó sang bên phải 1 hàng thì số đó tăng thêm 10 lần

ta có sơ đồ bn tự vẽ nha,số A là 10 phần,số B là 1 phần và số C là 100 phần

Tổng số phần bằng nhau là : 1+10+100=111(phần)

Số A là :221,778 : 111 x 10  = 19,98

Đ/S:19,98

=19,98 bạn ạ

đợi mình chút nhé

19,89 CHÚC BẠN HỌC TỐT

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