tính nhanh:
-13/8.(8/13+32/28)-15/7
Tính hợp lý
a, - ( - 15 ) - ( +27 ) + ( + 27 ) + ( -15 ) + ( -29)
b, 12 - ( a + 105 - 13 ) + ( 4 + 105 - 13 )
c, ( 5 + 7 - 8 ) - ( 7 + 5 - 8 )
d, - 15 - ( -17 + 21 - 35 ) + ( -17 + 21 - 35)
e, 32 - ( -7 - 28 + 15 ) - ( 7 + | -28 | + 32 )
f, -1379 - ( -1379 - 27 )
Làm giùm, cần gấp.
a. -7 – 9 =
b. -15 – 8 =
c. -28 – 32 =
d. -43 – 32 =
e. – 5 – 9 – 11 =
f. – 6 – 8 – 13 =
g. – 3 – 7 – 25 =
h. – 7 – 4 – 15 =
a. - 7 - 9 = - (7 + 9) = - 16
b. - 15 - 8 = - (15 + 8) = - 23
c. - 28 - 32 = - (28 + 32) = - 60
d. - 43 - 32 = - (43 + 32) = - 75
e. - 5 - 9 - 11
= - (5 + 9 + 11)
= - (14 + 11)
= - 25
f. - 6 - 8 - 13
= - (6 + 8 + 13)
= - (14 + 13)
= - 27
g. - 3 - 7 - 25
= - (3 + 7 + 25)
= - (10 + 25)
= - 35
h. - 7 - 4 - 15
= - (7 + 4 + 15)
= - (11 + 15)
= - 26
tính 1*2*3*4*5*6*7*8*9*10*11*12*13*14*15*16*17*18*19*0*20*21*22*23*24*25*26*27*28*29*30*31*32
ai nhanh mình tích cho
1*2*3*4*5*6*7*8*9*10*11*12*13*14*15*16*17*18*19*0*20*21*22*23*24*25*26*27*28*29*30*31*32=0
Bài 1 Tính nhanh
a) -3/7 + 5/13 + 3/7
b) -5/21+-2/21+8/24
c) -5/11+(-6/11+2)
d) (-1/32+1/2)+15/32
e)5/17+ -6/13 + 3/4 + 7/-13+12/17
f) 7/23+-18/18+-4/9+16/23+-5/8
g)1/3+-3/4+3/5+-1/36+1/15+-2/9
h)-1/2+1/3+-1/4+-2/8+4/18+4/9
a)\(-\dfrac{3}{7}+\dfrac{5}{13}+\dfrac{3}{7}\)
=\(\left(-\dfrac{3}{7}+\dfrac{3}{7}\right)+\dfrac{5}{13}\)
=\(0+\dfrac{5}{13}\)
=\(\dfrac{5}{13}\)
tính nhanh:
8/27 + 4/15 + 19/27 + 11/15
12/13 + 2/7 + 8/13 + 6/13 + 5/7
8/27+4/15+19/27+11/15
=(8/27+19/27)+(4/15+11/5)
=27/27+15/15
=1+1
=2
12/13 + 2/7 + 8/13 + 6/13 + 5/7
= ( 2/7 + 5/7 ) + ( 12/13 + 8/13 + 6/13 )
= 1 + 2
= 3
2/15-2/65-4/39
32/13-(7/23+8/23)
(1/3+12/67+13/41) - (79/67 - 28/41)
38/45 - (8/45-17/51-3/11)
2/15-2/65-4/39=4/39-4/39=0
32/13-(7/23+8/23)=32/13-15/23=541/299
(1/3+12/67+13/41) - (79/67 - 28/41)=6836/8241-1363/2747=1/3
38/145 - (8/45-17/51-3/11)=38/145-(-212/495)=1982/2871
Tính theo mẫu :
Mẫu : 13/21 + 5/7 = 13/21 + 5 x 3 / 7 x 3 = 13/21 + 15/21 = 28/21
26/81 + 4/27
5/64 + 7/8
\(\dfrac{26}{81}+\dfrac{4}{27}=\dfrac{26+12}{81}=\dfrac{38}{81}\)
\(\dfrac{5}{64}+\dfrac{7}{8}=\dfrac{5+56}{64}=\dfrac{61}{64}\)
\(\dfrac{26}{81}+\dfrac{4}{27}=\dfrac{26}{81}+\dfrac{4\times3}{27\times3}=\dfrac{26}{81}+\dfrac{12}{81}=\dfrac{38}{81}\)
\(\dfrac{5}{64}+\dfrac{7}{8}=\dfrac{5}{64}+\dfrac{7\times8}{8\times8}=\dfrac{5}{64}+\dfrac{56}{64}=\dfrac{61}{64}\)
tính nhanh 7/8 + 19/32 + 2/16 + 13/32
\(\frac{7}{8}+\frac{19}{32}+\frac{2}{16}+\frac{13}{32}\)
\(=\frac{14}{16}+\frac{19}{32}+\frac{2}{16}+\frac{13}{32}\)
\(=\left(\frac{14}{16}+\frac{2}{16}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)
\(=1+1=2\)
2.Tính (+5) + ( +4) = ? 3.Tính (- 9) + ( - 1) = ? 4.Tính : 28 + (-15) = ? 5.Tính (-15) + 12 = ? 6.Tính (-25) + 25 = ? 7.Tính : 13 - 17 = ? 8.Tính : (-78) - 9 = ? 9.Tính : ( -24) - ( - 16) = ? 10.Tính : 17 - (-3) = 11.Tính nhanh : (-21) - ( 48 + 52 - 21) = ?
2. Tính (+5) + ( +4) = 9
3.Tính (- 9) + ( - 1) = -10
4.Tính : 28 + (-15) = 13
5.Tính (-15) + 12 = - 3
6.Tính (-25) + 25 = 0
7.Tính : 13 - 17 = - 4
8.Tính : (-78) - 9 = - 87
9.Tính : ( -24) - ( - 16) = - 8
10.Tính : 17 - (-3) = 20
11.Tính nhanh : (-21) - ( 48 + 52 - 21) = -100
2, (+5)+(+4)=+9 hoạc 9 cũng được
3, (-9)+(-1)=-10
4, 28+(-15)=13
5, (-15)+12=-3
6, (-25)+25=0
7, 13-17=4
8, (-78)-9=-87
9, (-24)-(-16)=-40
10, 17-(-3)=20
11, (-21+21)-(48-52)=-4
2. (+5) + ( +4) = 9
3. (- 9) + ( - 1) = -10
4. 28 + (-15) = 13
5. (-15) + 12 = - 3
6. (-25) + 25 = 0
7. 13 - 17 = - 4
8. (-78) - 9 = - 87
9.( -24) - ( - 16) = - 8
10. 17 - (-3) = 20
11. (-21) - ( 48 + 52 - 21) = -100