Tính: (-17).6
Tính nhanh:
a) 47.29-13.29-24.29;
b) 26.7-17.9 + 13.26-17.11;
c) 1167:6 + 33:6;
d) 1754:17 - 74:17 + 20:17.
Đặt tính rồi tính :
17 x 4 20 x 6 17 : 4 96 : 3
Tính ( một cách hợp lí )
a, 18 . 17 - 3 .6 .7
b, 54 - 6 . ( 17 + 9 )
c, 33 . ( 17 - 5 ) - 17 . ( 33 - 5 )
\(a,18.17-3.6.7\)
\(=18.17-18.7\)
\(=18.\left(17-7\right)\)
\(=18.10\)
\(=180\)
\(b,54-6.\left(17+9\right)\)
\(=54-6.17+6.9\)
\(=54-102+54\)
\(=\left(54+54\right)-102\)
\(=108-102\)
\(=6\)
\(c,33.\left(17-5\right)-17.\left(33-5\right)\)
\(=33.17-33.5-17.33-17.5\)
\(=\left(33.17-17.33\right)-\left[5\left(33-17\right)\right]\)
\(=0-5.16\)
\(=-80\)
a) \(18.17-3.6.7\)
\(=18.17-18.7\)
\(=18.\left(17-7\right)\)
\(=18.10\)
\(=180\)
b) \(54-6.\left(17+9\right)\)
\(=54-102-54\)
\(=-102\)
c) \(33.\left(17-5\right)-17.\left(33-5\right)\)
\(=561-165-561+85\)
\(=-80\)
a , 18 . 17 - 3 . 6 . 7
= 18 .17 - 18 . 7
= 18 . ( 17 - 7 )
= 18 . 10
= 180
b , 54 - 6 . ( 17 + 9 )
= 54 - 6 . 17 + 6 . 9
= 54 - 102 + 54
= ( 54 - 54 ) - 102
= 0 - 102
= - 102
c , 33 . ( 17 - 5 ) - 17 . ( 33 - 5 )
= 33 . 17 - 33 . 5 - 17 . 33 - 17 .5
= 0 - 5 . 16
= 0 - 80
= - 80
Tính bằng cách thuận tiện:
47/15 + 40/17 - 4/30 - 6/17
Tính nhanh : 33 x (17 - 5 ) - 17 x ( 33 - 5 ) và 54 - 6 x ( 17 + 9 )
33 x ( 17 - 5 ) - 17 x ( 33 - 5 )
= 33 x 17 - 33 x 5 - 17 x 33 + 17 x 5
= ( 33 x 17 - 33 x 17 ) - 33 x 5 + 17 x 5
= 0 - 5 x ( 33 - 17 )
= -5 x 16
= -80
54 - 6 x ( 17 + 9 )
= 54 - 6 x 17 - 6 x 9
= 54 - 102 - 54
= ( 54 - 54 ) - 102
= 0 - 102 = -102
Ghi kết quả tính:
15 − 7 + 8 = ..... | 6 + 7 − 9 = ..... | 12 − 5 + 7 = ..... |
17 − 9 + 8 = ..... | 9 + 6 − 7 = ..... | 14 − 5 + 3 = ..... |
8 + 8 − 9 = ..... | 17 − 8 + 6 = ..... | 6 + 9 − 9 = ..... |
Phương pháp giải:
Tính nhẩm từ trái sang phải rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
15 − 7 + 8 = 16 | 6 + 7 − 9 = 4 | 12 − 5 + 7 = 14 |
17 − 9 + 8 = 16 | 9 + 6 − 7 = 8 | 14 − 5 + 3 = 12 |
8 + 8 − 9 = 7 | 17 − 8 + 6 = 15 | 6 + 9 − 9 = 6 |
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Đặt tính rồi tính:
a) 15 - 9 15 – 7
15 - 8 15 - 6
b) 16 - 7 16 – 9
16 - 8 17 - 8
c) 17 - 9 18 – 9
18 - 8 17 - 10
Phương pháp giải:
- Đặt tính: Viết phép tính sao cho các chữ số cùng hàng thẳng cột với nhau.
- Tính: Trừ các số rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
a)
b)
c)
Tính nhanh 6/11+ 25/17 + 5/11 - 8/17= ?
6/11+25/17+5/11-8/17
= (6/11+5/11)+(25/17-8/17)
= 11/11 + 17/17
= 1 + 1
= 2
Nhấn đúng cho mk nha Trần Đức Mạnh
\(\frac{6}{11}+\frac{25}{17}+\frac{5}{11}-\frac{8}{17}\)
=\(\left(\frac{6}{11}+\frac{5}{11}\right)+\left(\frac{25}{17}-\frac{8}{17}\right)\)
=1+1
=2
TÍNH NHANH
4/3+17/3+17/9+19/13+1/9+14/6=
A = \(\dfrac{4}{3}\) + \(\dfrac{17}{3}\) + \(\dfrac{17}{9}\) + \(\dfrac{19}{13}\) + \(\dfrac{1}{9}\) + \(\dfrac{14}{6}\)
A = (\(\dfrac{4}{3}\) + \(\dfrac{17}{3}\)) + (\(\dfrac{17}{9}\) + \(\dfrac{1}{9}\)) + (\(\dfrac{19}{13}\) + \(\dfrac{14}{6}\))
A = \(\dfrac{21}{3}\) + \(\dfrac{18}{9}\) + \(\dfrac{148}{39}\)
A = 7 + 2 + \(\dfrac{148}{39}\)
A = 9 + \(\dfrac{148}{39}\)
A = \(\dfrac{39\times9}{39}\) + \(\dfrac{148}{39}\)
A = \(\dfrac{499}{39}\)
/ Tính hợp lí
a ) 18 .17 -3 .6.7
b) 54-6 (17 + 9)
c) 33. (17-5) -17 .(33-5)
a/ 18.17-3.6.7
=18.6.3.(17-7)
=18.6.3.10
18.18.10
3240
a)=18.17-18.7
=18.(17-7)=18.10=180
b)=54-(6.17+6.9)=54-102-54=(54-54)-102=0-102=-102
c)=(33.17-33.5)-(17.33-17.5)=33.17-33.5-17.33+17.5=(33.17-17.33)-5.(33-17)=0-80=-80