b) Chia het cho 1 5.
B a i 43. Thay cac chu so a ; b bang ca c chu s6 thkh hqp sao cho: a) 234a4b chia h et cho 2; 3 va 5.
ARCH IMEDES SCHOOL
b) 22aab chi a het cho 2; 5 va 9.
c) 931a4b chi a het cho 2, chia 5 du 2 va chi a het cho 9.
d) 234a4b chia het cho 4 va 9
Bai 44. Them vao ben trai va ben phai so 879 moi ben 1 chu so de duqc so tV nhien
c6 5 ch u s6 chia 5 dv 2 va chia het cho 9.
Rise above oneself
and g rasp the world
Toan s - Quyen 4.1
Bai 98. The tkh, hlnh hqp chu nh�t se tang g ia m bao nhieu phan tram neu chieu dai giam di 1 0% va chh�u r¢ng giam di 1 0% va chi<�u cao tang them 20o/o.
Bai 99. Nhan ngay khai truong1 m¢t cua hang g iam g ici 1 0°!6. Nhung etta hang d6 van lai 1 7% moi lo�i hang h6a. Hoi neu khong h 9 g ia thl c U'a hang d6 ll1i bao nhieu
phan tram?
Bai 1 00. Mqt nguoi g ui tiE�t ki$m 1 00 tri�u dong v6'i I�H suat 015o/o m9t than g. Hoi sau 2 thang ng llai d6 linh dugc bao nhieu tien ca von lan lai ? Biet rang lai cua thang
tn.tac cGng nh�p tha n h von cua thang sau.
Bai 1 0 1 . Tr9n 400g dung d!ch nuoc bien 5o/o mu6i vai 200g dung dfch nu6'c bien 2o/o
muOi. Hoi dung djch nu6'c bien meri c6 bao nhieu phan tram muoi?
Archimedes School I 53
mua 1
muon lai 25% thl cua do m oi ki-16-g a m dubng gia bao tien?
Bid 96.. Vuan cay a n qua nha An tro n g ba lo�i: quyt, cam, buoi. 56 cay q uyt chiem 24o/o tong so cay. 56 cay cam chiem 42°/o tong so cay. Tfn h s6 cay q uyt, so cay camf biet vvan cay co 1 7 cay buoi.
Bai 97. Lop 6A c6 36o/o so h9c sinh xep lo<;1i gioi, 43g� so h9c si n h xep lo9 i kha, so con l�i xep l o9i tru ng b1 nh. Bh2t tong s6 hqc s i n h gioi va tru ng blnh Ia 26 em. Tln h s6
hQC sinh moi l09i.
Rise a bove oneself and g rasp the world
Co bao n hieu so tt! n hien co 2 chu so dong thai chia het cho 2 va 3?
Bai 47. C6 baa n h ieu so ttj n h ien c6 3 chG' so khong chia het cho 3?
9 1 .
Arch i medes School Asc h oo Led u.vn
ARCHIMEDES SCHOOL
B�ti 48. 11m so ttl . nhh?n be nhat khac 1 sao cho khj chi a so d6 cho 3; 4; 5 va 7 deu du 1 . .
Bai 49. 11m so tlj nhh?n be nhat chi a cho 3 dt.J 2, cho 4 dti 3, cho s du 4 va cho 7 du 6.
Bai 50. M(>t cU'a hang c6 6 thung xa bong. Khoi h.tqng trong cac thung I an J uqt Ia 1 5 kg; 1 6kg; 1 8kg; 1 9kg; 20kg va 3 1 kg. Cua hang ban het 5 thung. Biet khoi hiqng ban buoi sang gap doi khoi lu'c;tng bah buoi chieu. Hoi oia hang con l�i thung xa bong nao?
Rise above oneself
and grasp the world
Toan s -Quyen 4.1 Bai 92. Hai nguai thq cung lam chung mc?t cong vi�c thl sau 5 g io s� xong. Sau khi
. .
lam ctvqc 3 gio thl ngu'oi thq ca b�n nen de nguoi thq phl:l hoan thanh not vi�c d6 trong 6 gio. Hoi neu moi ngu'oi thq lam m(>t ml nh thl sau bao lau se xongvi$c d6?
Bai 93. Mqt be c6 hai voi nuacl m(>t chay vao va mqt chay ra. Voi chay vao chay 5
giO' thl day be. Voi chay ra se lam G� n be day trong 7 gio. Neu mo ca hai voi cu n g l uc
thl sau bao lau be day nvoc? (Biet rang ban dau be kh6ng c6 nlfoc)
Bai 94. C6 ba voi nu6'c chay vao m¢t be c�n. Neu md voi m9t va voi hai thl be day
sau : gio; neu voi hai va voi ba thl day be sau 2 gio; neu voi ba va voi m¢t cung chay thl day be sau � gio. Hoi voi thu ba chay rieng thl day be sau baa I au?
2 '
Archimedes School I 51 Aschool.edu.vn
Ba i 90. Be d�t ong n u6'c, 5 c6n g nhan dao trong 2 ngay auqc 20m d.uong. Hoi 20 cong n han aao trong 6 n gay auqc bao n h i eu met duang?
Ba i 9 1 .. Ba n guoi cung lam m¢t c6n£! vi$c. Neu lam mc;>t ml n h moi nguoi lan h1Qt lam
xon g trong 3 gia, 6 gia, 2 g ia. Hoi neu ca ba n g lioi cung lam thl sau bao lau se xon g
cong vi$c do?
Rise above oneself
and grasp the world
ta a a
luc dau?
7
s6 3 so Hoi
ARCH I MEDES SCHOOL
IV .. ON T�P VE TiNH TOA�
A. LY THUY�T
Cac tfnh chat can nho:
• Tlnh chat giao hoan cua phep c¢ng: a + b = b + a • Tfn h chat giao hoan cua phep nhan: a x b = b x a
• Tf n h chat ket hQp: a + b + c = a + (b + c)
• Quy tac b6 dau ngo�c:
· a -(b + c) = a -b -c a -(b -c) = a -b + c
• Tlnh chat cua phep chia: a : (b x c) = a : b : c
• Nhan m¢t so voi mgt tong (hi�u): ax(b±c)=axb±axc B . Vi Dl) MINH HQA Vi dy 1 : Tinh hqp ly a) 50 X 24,5 + 49 X 24,5 + 24,5 b) (792,8 1 X 0,25 + 79�,81 X 0,75) X ( 1 1 X 9 - 900 X 0,1 - 9) Bai lam: a) 50 X 24,5 + 49 X 24,5 + 24,5 = 24,5 X {50 + 49 + 1 ) = 24,5 X 1 00 = 2450 b) {792,8 1 X 0,25 + 792,8 1 X 0,75) X (1 1 X 9 - 900 X 011 -9) = 792,8 1 X (0,25 + 0,75) X {99 - 90 - 9) = 792,81 X 1 X 0 = 0 C. BAI T�P
Bai 52. Tfn h bang each hqp ly gla tr� cac biE�u thuc sau: a) 60 - 26,75 - 1 3,25
Rise above oneself
and g rasp the world
Toan 5 -Quyen 4.1 VIII. ON T�P VE Ti L� THU�N, Ti L� NGH,CH, CONG VI�C CHUNG
Biti 86. Muon aao m9t cai ao thl can 80 nguoi lam trong 20 n gay .. Hoi neu m uo n