Đề thi học sinh giỏi vòng 2 Toán Lớp 5 - Năm học 2008-2009 - Trường Tiểu học Tam Thanh
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Phòng GD&ĐT thành phố Đề khảo sát học sinh giỏi lớp 5 vòng2 Trường tiểu học Tam Thanh Năm học: 2008 – 2009 Môn: Toán Thời gian làm bài 90 phút (Không kể thời gian giao đề) Bài 1: (5điểm) Tính giá trị biểu thức bằng cách nhanh nhất: 117 x ( 360 + 620 ) – 17 x ( 620 + 360 ) .......................................................................................................................................................................................................................................................................................................................................... ........................................................................................................................................................................................................................................................................................................................................... ............................................................................................................................................................................................................................................................................................................................................ ............................................................................................................................................................................................................................................................................................................................................ ........................................................................................................................................................................................................................................................................................................................................... ........................................................................................................................................................................................................................................................................................................................................... ( 45 x 46 + 47 x 48 ) x ( 45 x 130 – 90 x 65 ) .......................................................................................................................................................................................................................................................................................................................................... ........................................................................................................................................................................................................................................................................................................................................... ............................................................................................................................................................................................................................................................................................................................................ ............................................................................................................................................................................................................................................................................................................................................ ........................................................................................................................................................................................................................................................................................................................................... ........................................................................................................................................................................................................................................................................................................................................... Bài 2:(6 điểm ) a)Tìm một số tự nhiên có 2 chữ số, biết rằng nếu viết thêm một chữ số 1 vào bên trái của số đó thì ta được số mới gấp 5 lần số đã cho. b)Lớp 5A và lớp 5B trồng được một số cây. Biết trung bình cộng số cây hai lớp đã trồng bằng 235 cây và nếu lớp 5A trồng thêm 80 cây, lớp 5B trồng thêm 40 cây thì số cây hai lớp đẫ trồng sẽ bằng nhau. Tìm số cây mỗi lớp đã trồng? 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Bài 3:( ( 3điểm ) Một người bán vải, buổi sáng bán được tấm vải. Buổi chiều bán được chỗ vải còn lại thì tấm vải chỉ còn 12 m. Hỏi: Tấm vải dài bao nhiêu mét? Mỗi buổi bán được bao nhiêu mét? 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