4-1/2x5/7=???
6 x5/3 7:8/4+1/3 2x5/8-1/2 3/7:5/6x1/4
10
\(\dfrac{23}{6}\)
\(\dfrac{3}{4}\)
\(\dfrac{9}{70}\)
6 x5/3=10 7:8/4+1/3=23/6 2x5/8-1/2=3/4 3/7:5/6x1/4=9/70
Bài 1 tính bằng cách thuận tiện nhất: 3/2x5/7+3/2x2/7+1/4
Trả lời
3/2.5/7+3/2.2/7+1/4
=3/2.(5/7+2/7)+1/4
=3/2.1+1/4
=3/2+1/4
=6/4+1/4
=7/4
3/2x5/7+3/2x2/7+1/4
= 3/2 x ( 5/7 + 2/7 ) + 1/4
= 3/2 x 1 + 1/4
= 3/2 + 1/4
= 6/4 + 1/4
= 7/4
\(\frac{3}{2}.\left(\frac{5}{7}+\frac{2}{7}\right)+\frac{1}{4}=\frac{3}{2}.1+\frac{1}{4}=\frac{3}{2}+\frac{1}{4}=\frac{7}{4}=1,75\)
tính tổng sau:
S= 1 x 4 + 2x5 + 3 x 6 + 4 x 7 + ......... + n x (n + 3)
Trong các phép tính sau, những phép tính nào làm đúng? ( CHỌN NHIỀU ĐÁP ÁN )
A 3/4 + 1/3 = 3+1 /4 + 3 = 4/7
B 7/9 - 1/3 = 7- 1/ 9- 3 = 6/6 = 1
C 6/7 x 2/5 = 6x2 / 2x5 = 12/35
D 5/6 : 1/3 = 5/6 x 3/1 = 5/2
A . 2/5x3/7 4/9x3/10 4/7x3/4 2x5/8
B . 3/8:7/5 3/4:9/10 7/8:2 6:2/3
C . 1/3x3/5x5/9 15/16:3/8x3/4
1/2x5/7+23/12-3/2:34/1
tính
(2^2+1) x (2^2 -1) x (2^4 - 4^2)
(7^3+7^5) x (5^4+5^6) x (3^3 x 3-9^2)
2^2x5 [( 5^2 + 2^3) : 11] - 2^4 + 2 x 10^3
(2 ^ 2 + 1) x (2 ^ 2 - 1) x (2 ^ 4 - 4 ^ 2)
= (2 ^ 2 + 1) x (2 ^ 2 - 1) x ( 16 - 16 )
= (2 ^ 2 + 1) x (2 ^ 2 - 1) x 0
= 0
( 7 ^ 3 + 7 ^ 5) x (5 ^ 4 + 5 ^ 6) x ( 3 ^ 3 x 3 - 9 ^ 2)
= ( 7 ^ 3 + 7 ^ 5) x (5 ^ 4 + 5 ^ 6) x ( 3 ^ 4 - 3 ^ 4)
= ( 7 ^ 3 + 7 ^ 5) x (5 ^ 4 + 5 ^ 6) x 0
= 0
2 ^ 2 x 5 [( 5 ^ 2 + 2 ^ 3) : 11] - 2 ^ 4 + 2 x 10 ^ 3
= 4 x 5 [( 25 + 8 ) : 11] - 8 + 2 x 1000
= 20 ( 33 : 11) - 8 + 2000
= 20 x 3 - 8 + 2000
= 60 - 8 + 2000
= 2052
1+2x5+6x5-8-8x69-969+5x5+6+4+4+4-5x6
3/5^2x5^2-2 1/4^3 :3/4^3 + 1/2