Tính: 3 4 × 16 9 = . . .
1.Tính
a)15/16 - 7/16 b)7/4 - 3/4 c)9/5 - 3/5 d) 17/49 - 12/ 49
Lưu ý không tính: 15/16 - 7/16 =8/16 2.
Rút gọn rồi tính
a) 2/3 -3/9 b)7/5 - 15/25
Bài 1: Tính
\(a.\frac{15}{16}-\frac{7}{16}=\frac{15-7}{16}=\frac{8}{16}=\frac{1}{2}\)
\(b.\frac{7}{4}-\frac{3}{4}=\frac{7-3}{4}=\frac{4}{4}=1\)
\(c.\frac{9}{5}-\frac{3}{5}=\frac{9-3}{5}=\frac{6}{5}\)
\(d.\frac{17}{49}-\frac{12}{49}=\frac{17-12}{49}=\frac{5}{49}\)
Bài 2:Rút gọn rồi tính
\(a.\frac{2}{3}-\frac{3}{9}=\frac{2}{3}-\frac{1}{3}=\frac{2-1}{3}=\frac{1}{3}\)
\(b.\frac{7}{5}-\frac{15}{25}=\frac{7}{5}-\frac{3}{5}=\frac{7-3}{5}=\frac{4}{5}\)
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40000000000000+09999999999999999999999=.....,..............,.......,........
Giúp mình với ạ Bài 1 Tính 1) 2/9 + -3/4 + 5/30 2) -7/12 - 11/18 3) 7/8 - -5/16 4) 3/8 - -9/10 - 5/16
1)` 2/9 + -3/4 + 5/30= (40+(-135) + 30 )/180 = -65/180 = -13/36`
2) `-7/12 - 11/18=(-21)/36 - 22/36 = -43/36 `
3) `7/8 - (-5)/16=14/16- (-5)/16 = 19/16 `
4) `3/8 - (-9)/10 - 5/16= (30- (-72) -25)/80=77/80`
1)\(\dfrac{2}{9}+\dfrac{-3}{4}+\dfrac{5}{30}\)
\(=\dfrac{2.20}{9.20}+\dfrac{-3.45}{4.45}+\dfrac{5.6}{30.6}\)
\(=\dfrac{40}{180}+\dfrac{-135}{180}+\dfrac{30}{180}\)
\(=\dfrac{40+\left(-135\right)+30}{180}\)
\(=\dfrac{-65}{180}\)
\(=\dfrac{-13}{36}\)
2)\(\dfrac{-7}{12}-\dfrac{11}{18}\)
\(=\dfrac{-7.3}{12.3}-\dfrac{11.2}{18.2}\)
\(=\dfrac{-21}{36}-\dfrac{22}{36}\)
\(=\dfrac{-21-22}{36}\)
\(=\dfrac{-43}{36}\)
3)\(\dfrac{7}{8}-\dfrac{-5}{16}\)
\(=\dfrac{7.2}{8.2}-\dfrac{-5}{16}\)
\(=\dfrac{14}{16}-\dfrac{-5}{16}\)
\(=\dfrac{14-\left(-5\right)}{16}\)
\(=\dfrac{19}{16}\)
4)\(\dfrac{3}{8}-\dfrac{-9}{10}-\dfrac{5}{16}\)
\(=\dfrac{3.10}{8.10}-\dfrac{-9.8}{10.8}-\dfrac{5.5}{16.5}\)
\(=\dfrac{30}{80}-\dfrac{-72}{80}-\dfrac{25}{80}\)
\(=\dfrac{30-\left(-72\right)-25}{80}\)
\(=\dfrac{77}{80}\)
Tính nhanh:
3/8 + 9/2 X 12/16 - 9/4 : 3
3/8 + 9/2 x 3/4 - 9/4 x 1/3
= 3/8 + 9/2 x 3/4 - 3/4
= 3/8 + (9/2 - 1) x 3/4
= 3/8 + 7/2 x 3/4
= 3/4 x 1/2 + 7/2 x 3/4
= 3/4 x ( 1/2 + 7/2 )
= 3/4 x 4
= 3
Tính nhanh:
3/8 + 9/2 X 12/16 - 9/4 : 3
3/8 + 9/2 x 3/4 - 9/4 x 1/3
= 3/8 + 9/2 x 3/4 - 3/4
= 3/8 + (9/2 - 1) x 3/4
= 3/4 x 1/2 + 7/2 x 3/4
= 3/4 x ( 1/2 + 7/2)
= 3/4 x 4
= 3
Tính bằng cách thuận tiện:
A)2/9+3/9+4/9+5/9+6/9+7/9
B)1/6+4/9+5/6+11/16+5/9+5/16
2/9+3/9+4/9+5/9+6/9+7/9
=2+3+4+5+6+7/9
=27/9
=3
1/6+4/9+5/6+11/16+5/9+5/16
=1/6+5/6+4/9+5/9+11/16+5/16
=1+1+1=3
hok tốt ~
Tính nhẩm:
14 − 9 = ..... | 16 − 7 = ..... | 12 − 8 = ..... | 6 + 9 = ..... |
8 + 8 = ..... | 11 − 5 = ..... | 13 − 6 = ..... | 18 − 9 = ..... |
14 − 6 = ..... | 17 − 8 = ..... | 12 − 5 = ..... | 3 + 9 = ..... |
9 + 4 = ..... | 11 − 9 = ..... | 3 + 8 = ..... | 16 − 8 = ..... |
Phương pháp giải:
Tính nhẩm các số rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
14 − 9 = 5 | 16 − 7 = 9 | 12 − 8 = 4 | 6 + 9 = 15 |
8 + 8 = 16 | 11 − 5 = 6 | 13 − 6 = 7 | 18 − 9 = 9 |
14 − 6 = 8 | 17 − 8 = 9 | 12 − 5 = 7 | 3 + 9 = 12 |
9 + 4 = 13 | 11 − 9 = 2 | 3 + 8 = 11 | 16 − 8 = 8 |
Tính nhẩm:
14 − 9 = ..... | 16 − 7 = ..... | 12 − 8 = ..... | 6 + 9 = ..... |
8 + 8 = ..... | 11 − 5 = ..... | 13 − 6 = ..... | 18 − 9 = ..... |
14 − 6 = ..... | 17 − 8 = ..... | 12 − 5 = ..... | 3 + 9 = ..... |
9 + 4 = ..... | 11 − 9 = ..... | 3 + 8 = ..... | 16 − 8 = ..... |
TÍNH : 15^9 . 16^4/ 12^9 . 125^3
\(\frac{15^9.16^4}{12^9.125^3}=\frac{\left(3.5\right)^9.\left(2^4\right)^4}{\left(3.4\right)^9.\left(5^3\right)^3}=\frac{3^9.5^9.2^{16}}{3^9.4^9.5^9}=\frac{2^{16}}{4^9}=\frac{2^{16}}{\left(2^2\right)^9}=\frac{2^{16}}{2^{18}}=\frac{1}{4}\)
Tính bằng cách thuận tiện nhất
A) 39/16 : 5/8 - 7/16 : 5/8
b) 4/3 X 9/8 - 4/3 X 3/8
`39/16 : 5/8 - 7/16 : 5/8`
`=39/16 xx 8/5- 7/16 xx 8/5`
`=8/5 xx (39/16 - 7/16)`
`= 8/5 xx2`
`= 16/5`
__
` 4/3 xx 9/8 - 4/3 xx 3/8`
`=4/3 -(9/8 - 3/8)`
`= 4/3 xx 3/4`
`=1`
\(a,\\ \dfrac{39}{16}:\dfrac{5}{8}-\dfrac{7}{16}:\dfrac{5}{8}\\ =\dfrac{39}{16}\cdot\dfrac{8}{5}-\dfrac{7}{16}\cdot\dfrac{8}{5}\\ =\dfrac{8}{5}\cdot\left(\dfrac{39}{16}-\dfrac{7}{16}\right)=\dfrac{8}{5}\cdot2=\dfrac{16}{5}\\ b,\\ \dfrac{4}{3}\cdot\dfrac{9}{8}-\dfrac{4}{3}\cdot\dfrac{3}{8}=\dfrac{3}{2}-\dfrac{1}{2}=1\)
a)
`39/16:5/8-7/16:5/8`
`=(39/16-7/16):5/8`
`=32/16xx8/5`
`=2xx8/5`
`=16/5`
b)
`4/3xx9/8-4/3xx3/8`
`=4/3xx(9/8-3/8)`
`=4/3xx6/8`
`=4/3xx3/4`
`=1`
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
Tính:
3/4-3/12
16/9-18/27
\(\dfrac{3}{4}-\dfrac{3}{12}=\dfrac{3\times3}{4\times3}-\dfrac{3}{12}=\dfrac{9}{12}-\dfrac{3}{12}=\dfrac{9-3}{12}=\dfrac{6}{12}=\dfrac{1}{2}\\ \dfrac{16}{9}-\dfrac{18}{27}=\dfrac{16}{9}-\dfrac{2}{3}=\dfrac{16}{9}-\dfrac{2\times3}{3\times3}=\dfrac{16}{9}-\dfrac{6}{9}=\dfrac{16-6}{9}=\dfrac{10}{9}\)
9/12 - 3/12 = 3/12
48/27 - 18/27 = 30/27
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