đề thi HSG Toán lop 5 có đáp án

Đề 1 – Lớp 5
Bài 1: a) Tính giá trị của biểu thức sau:
A =

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b) Tính nhanh;


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Bài 2: Tổng chiều dài của ba tấm vải xanh, trắng, đỏ là 108 m. Nếu cắt tấm vải xanh, tấm vải trắng, tấm vải đỏ thì phần còn lại của ba tấm vải dài bằng nhau. Tính chiều dài mỗi tấm vải?
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Bài 3: Một cái hồ hình chữ nhật dài 4m, rộng2,5 m và cao 1,8m, hiện chứa 1500 lít nước. Lúc 7 giờ 38 phút người ta cho nước vào hồ. Vòi thứ nhất mỗi phút chảy được 40 l nước, vòi thứ 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 hạ giá 10%. Tuy vậy vẫn lãi 8%. Hỏi 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 thì 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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Đề 2 – Lớp 5
Bài 1: a) Tính giá trị của biểu thức sau:
A =
: 2

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b) Tính nhanh;



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c. Hãy cho biết có tất cả bao nhiêu phân số mà tích giữa tử số và mẫu số bằng 90?
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Bài 2: Hai người cùng làm thì sau 5 giờ sẽ xong. Sau khi làm được 3 giờ thì người thợ cả bận việc phải nghỉ. Một mình người thứ hai phải làm nốt công việc trong 6 giờ. Hỏi nếu mỗi người thợ làm một mình thì mất mấy giờ mới xong?
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Bài 3: Một bếp ăn chuẩn bị gạo cho 120 người ăn trong 50 ngày. Nhưng sau đó có một số người đến thêm, nên số gạo chỉ đủ ăn trong 30 ngày. Hỏi số người đến thêm là bao nhiêu?
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Bài 4: Một người mua kỳ phiếu loại 3 tháng với lãi suất 2% với giá trị kỳ phiếu là 6 000 000 đ. Hỏi sau 3 tháng người đó lĩnh bao nhiêu tiền cả vốn lẫn lãi. Biết rằng số tiền lãi tháng trước nhập thành tiền vốn tháng sau.
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Bài 5: Biết rằng tuổi Tuấn có bao nhiêu ngày thì tuổi bố có bấy nhiêu tuần; tuổi Tuấn có bao nhiêu thángthì tuổi Ông có bấy nhiêu năm. Ông hơn Bố 30 tuổi. Tính tuổi mỗi người?
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Bài 6: Một thùng hình hộp chữ nhật chứa đầy sữa nặng40 kg. Người ta lấy số sữa và thay bằng nước lã thì thấy chỉ còn nặng 39,7kg. Biết 1 lít sữa nặng 1,03kg; 1 lít nước nặng 1 kg. Hỏi:
a) Thể tích của cái thùng?
b) Chiều cao của cái thùng; biết rằng đáy dài 3 dm, rộng 2 dm?
c) Khối lượng của thùng rỗng?
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Đề 3 – Lớp 5
Bài 1: Cho P = 53, 2 : ( x – 3,5) + 45,8
a) Tính giá trị của P khi x = 7,5
b) Tính giá trị của x để P là số lớn nhất có 2 chữ số
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c) Tính

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Bài 2: Khi thực hiện phép chia hai số tự nhiên thì được thương là 6 dư 51. Tổng của số bị chia, số chia, thương và số dư là 969. Tìm số bị chia, số chia trong phép chia này.
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Bài 3