`5/39xx(7 4/5xx1 2/3+8 1/3xx7 4/5)`
`=5/39xx(39/5xx5/3+25/3xx39/5)`
`=5/39xx39/5(5/3+25/3)`
`=1xx30/3`
`=10`
539×(745×123+813×745)539×(745×123+813×745)
=539×(395×53+253×395)=539×(395×53+253×395)
=539×395(53+253)=539×395(53+253)
=1×303=1×303
=10
`5/39xx(7 4/5xx1 2/3+8 1/3xx7 4/5)`
`=5/39xx(39/5xx5/3+25/3xx39/5)`
`=5/39xx39/5(5/3+25/3)`
`=1xx30/3`
`=10`
539×(745×123+813×745)539×(745×123+813×745)
=539×(395×53+253×395)=539×(395×53+253×395)
=539×395(53+253)=539×395(53+253)
=1×303=1×303
=10
1/2x1/3+1/3x1/4+1/4x1/5+1/5x1/6+1/6x1/7+1/7x1/8+1/8x1/9
a.7/12+-5/8+2/3
b.2/7+3/4
c.-5/6+2/9+7/12
d.-5/6-7/8
e.-2/13-3/7+-2/3x7/7
f.(-5,6)x2+7,8
g.2,8:(-0,7)
a)2(x-5)+3(3-x)=5
b) 39x+2)-4(x-5)-24
-1/39x(3-13)+2/-6(x-6)=-3/8(x+4)
Bài 42. Dùng tính chất phân phối của phép nhân với phép cộng để tính:
1) 5(-3+2)– 7(5- 4)
2) –3(4– 7)+5(-3+ 2
3) 4(5– 3)+2(-4+6);
4) –5(2–7)+ 4(2-5)
5) 6(-3– 7) -7(3+5)
6) 3(-5+ 6) – 4(3–2)
7) -5(2– 3)– 7(4-2)
8) 7(3– 5)– 9(2-7);
9) -8(4– 5)+ 7(8– 4);
10) –2(5-7)+4(5- 3).
1-2-3-4-5-6-7-8-9-0+4+9+1+2+3+4+5:3:5:6:67:8:96+7+8+9+9-2-3-4-5-6-7-8-9-2+4+2+1+3+4+5+6+7+9+0+8+67?
LÂY BÚA CHAC ĐẦU ĐUÔI HỎI =?
Tính 1) 4/5 +13/18 2) 3/7 -11/8 3) -7/10 - -4/5 4) 3/20 -1/25 5) 2/3 - 5/6 6) 1/4 + -3/8 - 19/10 7) -9/10 - -7/18 8) 3/10 - 11/18 9) 3/5 -5/6 + -7/12 10) -4/9 - (-5 )/6 - 3/8
Bài 1: Tìm x:a) x - 2 + 7 = 1 . 3 . -9 b) 4 . x - 1 = (-5) 5 12 2 4 16 9 2 9c) -2 . x + 5 = 7 d) 2 . x : 7 . 1 = 29 3 8 12 5 3 8 15Bài 2: Tính:a) 2 + 1 . 4 b) 0,8 : [ 4 . 1,25] - [ 0,64 - 1 ] 5 7 5 25--------------------- 8 - 1 : 3 2 5 c) 8 : [ 7 - 12 ] d) ( 1,08 - 2 ) : 4 + ( 59 - 13 ). 36 9 2 7 25 7 9 4 17----------------------- [ 5 - 1 ] : 4
Thực hiện phép tính:
1,-4/7 + 2/3x -9/14
2,17/13 - ( 4/13 - 11 )
3, 8 2/7 - ( 3 4/9 + 4 2/7 )
5, ( 2/3 - 1 1/2): 4/3 + 1/2
6, -5/13 + 2/5 + -8/13 + 3/5 - 3/7
7, 6/5 x 3/7 + 6/5 : 7/10 + 6/5