TÊN: ĐỀ 1 Câu 1 : Số nào trong các số sau đây chia hết cho 5 mà không chia hết cho 2 ? A) 222 B) 2015 C) 118 D) 990 Câu 2 : Tập hợp tất cả các ước của 15 là: A) B) C) D) Câu 3 : Số có tổng các chữ số chia hết cho 9 thì chia hết cho: A) 36 B) 27 C) 18 D) 9 Câu 4 : Số có chữ số tận cùng bằng 0; 2; 4; 6; 8 thì chia hết cho: Câu Đúng Sai a) Nếu một số chia hết cho 9 thì số đó chia hết cho 3 b) Nếu một tổng chia hết cho một số thì mỗi số hạng của tổng chia hết cho số đó. c) Nếu a x , b x thì x là ƯCLN (a,b) d) Nếu hai số tự nhiên a và b có ƯCLN (a,b) = 1 thì a và b nguyên tố cùng nhau II. TỰ LUẬN : (7 điểm) Bài 1: Phân tích các số sau ra thừa số nguyên tố : 51; 75; 42; 270 Bài 2: Hãy điền vào dấu * để số a/ Chia hết cho 9 b/ Chia hết cho 5 và 3 Bài 3: a) Tìm ƯC ( 36,84 ) bằng cách tìm ƯCLN ( 36,84 ). b) Tìm BC ( 60, 180 ) bằng cách tìm BCNN ( 60, 180 ) Bài 3: Số học sinh khối 6 của trường trong khoảng từ 200 đến 400. Khi xếp hàng 12, hàng 15 , hàng 18 đều vua đủ. Tính số học sinh của khối 6. .................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 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TÊN:............................ ĐỀ 2: Bài 1: (1,0 điểm) a) Thế nào là số nguyên tố? Thế nào là hợp số? b) Viết các số nguyên tố bé hơn 20 Bài 2: (2 điểm) Không tính tổng và hiệu, xét xem tổng hiệu sau có chia hết cho 9 không? a) 234 + 135 ; b) 581 – 7. 18 Bài 3: (2,0 điểm) Phân tích các số sau ra thừa số nguyên tố: 56 và 288 Bài 4: (3,0 điểm) Bằng cách phân tích các số ra thừa số nguyên tố, hãy: a) Tìm ƯC(30, 18) b) Tìm BC (20, 24). Bài 5: (2,0 điểm) Một giá sách có khoảng 150 đến 200 CUỐN . Nếu xếp thành chồng 10 cuốn , 12 cuốn hay 15 cuốn thì vừa đủ, . Hỏi giá sách có bao nhiêu cuốn? .............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
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