tim UCLN {84;120;240} bang cach phan tich casc thua so nguyen to
tim ucln cua 24, 84 , 180
Ta có: 24 = 23 x 3
84 = 22 x 3 x7
180 = 22 x 32 x 5
=> UCLN(24;84;180) = 22 x 3 = 12
tim UCLN cua 24 ; 84 ; 180
Ta có 24 = 23 . 3; 84 = 22 . 3 . 7; 180 = 22 . 32 . 5.
Vậy ƯCLN (24, 84, 180) = 22 . 3 = 12.
1,tim 2 so tu nhien biet tong chung = 66 UCLN=6 co 1 so chia het cho 5
2,tim 2 so tu nhien biet hieu chung = 84 UCLN = 12
3,tim 2 so tu nhien biet tich = 864 UCLN=6
4,cho 3n+1 va 5n+4 la 2 so nguyen to cung nhau tim UCLN cua 3n+1 va 5n+4
5,cho a=123456789;b=987654321 . Tim UCLN cua a va b
tim 2 so tu nhien biet hieu cua chung bang 84 va UCLN bang 12
Biet rang : BCNN(a,b).UCLN(a,b)
a, BCNN cua hai so la 600, UCLN cua chung nho hon 10 lan BCNN. So thu 1 la 120, tim so thu 2.
b, UCLN cua hai so la 12, BCNN cua chung lon gap 6 lan UCLN . So t 1 la 24, tim so t 2
c, Tong cua hai so bang 60, tong giua UCLN va BCNN cua chung la 84. Tim hai so do.
tim 2so tu nhien biet hieu cua chung =84 va UCLN cua chung =12
Tim hai so tu nhien biet:
a) Tong cua chung bang 78 va UCLN bang 6
b) Hieu cua chung bang 84 va UCLN bang 12
c) Hieu cua chung bang 90 va UCLN bang 15
Giải:
a) Gọi 2 số cần tìm là a,b
\(=>a+b=78\left(1\right)\) ; \(\left(a;b\right)=6\left(2\right)\)
\(\left(1\right)=>a=6.m;b=6.n\) \(\); \(\left(m;n\right)=1\)
\(\left(1\right);\left(2\right)=>6.m+6.n=78\)
\(=>6\left(m+n\right)=78\)
\(=>m+n=13\) ; \(\left(m;n\right)=1\)
Ta có bảng sau:
m | 1 | 12 | 2 | 11 | 3 | 10 | 4 | 9 | 6 | 7 | 5 | 8 |
n | 12 | 1 | 11 | 2 | 10 | 3 | 9 | 4 | 7 | 6 | 8 | 5 |
=>
a | 6 | 72 | 12 | 66 | 18 | 60 | 24 | 24 | 36 | 42 | 30 | 48 |
b | 72 | 6 | 66 | 12 | 60 | 12 | 54 | 54 | 42 | 36 | 48 | 30 |
tim hai so tu nhien khi biet tong cua chung la 84 va UCLN cua chung la 12
tim hai so tu nhien:
tong cua hai so la 84,UCLN cua chung la 12
tim hai so tu nhien:
tong cua hai so la 84,UCLN cua chung la 12