De 2 lọp 5(hoc sinh gioi)

Đề 1 lớp 5(học sinh giỏi)


Bài 1:a) Tính gá trị của biểu thức sau:
1 6
10-1- x -
3 7
A=-----------------
11 2
21: --- +5---
2 11
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b) Tính nhanh:
8,1 : 0,6 x 1875 + 1,5 x 625 x 9
105 + 205 + 795 + 895

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Bài 2: Tổng chều dài của 3 tấm vải xanh, trắng, đỏ là 108 m. Nếu cắt 3 tấm
7
vải xanh, 1 tấm vải trắng, 1 tấm vải đỏ thì phần còn lại của 3 tấm vải dài
5 3
bằng nhau. Tính chiều dài mỗi tấm vải?

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Bài 3:Một cái hồ hình chữ nhật dài,rộng 2,5m và cao 1,8m, hiện chứa 1500 lít nước. Lúc 7h38p người ta cho nước vào hồ. Vòi thứ nhất mỗi phút chảy được 40 lít nước, vòi thú hai mỗi phút chảy hơn vòi thứ nhất 20 lít. Hỏi hồ đầy nước vào lúc mấy giờ?

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Bài 4: Một cửa hàng sách giá 10%. Tuy vậy vẫn lãi 8%,nếu không hạ giá, cửa hàng đó bán được lãi bao nhiêu phần trăm?
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Bài 5: Bố 38 tuổi, con 11 tuổi. Khi nào tuổi bố gấp 2 lần tuổi con?
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Bài 6 :Tìm số có 3 chữ số nhỏ nhất mà khi chia cho 2; 3; 4; 5; 6 có cùng số dư là 1
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