13 × 4 – 13 + 13 × 27+ 13 × 70 = 13 × (3 + 27 + 70)

= 13 × 100 = 1300

ta có cách tính nhanh như sau :

= 13 x ( 27 + 70 + 4 - 1 )

= 13 x 100

= 1300

nhé !

13 * 27 + 13 * 70 + 13 * 4 - 13

= 13 * 27 + 13 * 70 + 13 * 4 - 13 * 1

= 13 * ( 27  + 70 + 4 - 1 )

= 13 *         100

=     1300

13 x 27 + 13 x 70 + 13 x 4 - 13

= 13 x 27 + 13 x 70 + 13 x 4 - 13 x 1

= 13 x ( 27 + 70 + 4 - 1 )

= 13 x 100 

= 1300

13* 27 + 13 * 70 + 13 * 4 - 13

= 13* 27 + 13 * 70 + 13 * 4 - 13 x 1

= 13 * ( 27 + 70 + 4 - 1 )

= 13 * 100

= 1300

\(13\times27+13\times70+13\times4-13\)

\(13\times27+13\times70+13\times4-13\times1\)

\(=13\times\left(27+70+4-1\right)\)

\(=13\times100\)
\(=1300\)

13* 27 + 13 * 70 + 13 * 4 - 13

=13* 27 + 13 * 70 + 13 * 4 - 13*1

=13*(27+70+4-1)

=13*100

=1300

2

3

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

3

8/27+4/5+19/27+11/15=(8/27+19/27) + (4/5+11/15)

                                    = 1+ (12/15+11/15)

                                    = 1+ 1/8/15=2/8/15

12/13+2/7+8/13+6/13+5/7=(12/13+8/13+6/13) + (2/7+5/7)

                                         = 2+ 1

                                         =3

Ý a có thể bạn chép nhầm 4/5 rồi

= 2 + 1=3 nhé bạn

a: =(8/27+19/27)+(4/15+11/15)=1+1=2

b: =(12/13+8/13+6/13)+(2/7+5/7)=2+1=3

27,3-16,14=11,16

27(16-13)-16(27-13)

=27.16-27.13-16.27+16.13

=(27.16-16.27)+(-27.13+16.13)

=0+13(-27+16)

=0+13.-11

=0+-143=-143

Trả lời :

  27 .( 16 - 13 ) - 16 . ( 27 - 13 )

= 27 . 16 - 27 . 13 - 16 . 27 + 16 . 13

= ( 27 . 16 - 16 . 27 ) + 16 . 13 - 27 .13 

=   0  + 13 . ( 16 - 27 )

=   13 . ( - 11 )

=     - 143

- Study well -

13/18

=13/18x(41/27-14,27)

=13/18x1

=13/18

41/27*13/18-13/18*14/27

41/27*       0        *14/27=

         0               *14/27=0

Bài 2: 

a: =43cm

b: =42cm

c: =39cm

d: =17cm

Bài 1

=33

=45

=82

=45

=45

=47

=17

=45

Bài 2

=43 cm

=42 cm

=39 cm

=17 cm