745 + 268 + 732= 745 + ( 268 + 732 )

= 745 + 1000 = 1745

\(26\times8+4\times13-10\times26\)
\(=26\times8+2\times2\times13-10\times26\)
\(=26\times8+2\times26-10\times26\)
\(=26\times\left(8+2-10\right)\)
\(=26\times0\)
\(=0\)
#Đang Bận Thở

\(26\times8+4\times13-10\times26\\ =13\times2\times8+4\times13-10\times2\times13\\ =13\times\left(2\times8+4-10\times2\right)\\ =13\times0\\ =0\)

O

a) 1268 + 99 + 501= 1268 + ( 99 + 501)

…= 1268 + 600 = 1868

745 + 268 + 732= 745 + ( 268 + 732 )

= 745 + 1000 = 1745

1295 +105 + 1460= 1400 + 1460

= 2860

Ngu hết

415 x 42 + 415 x 33 + 415 x 25

= 415 x ( 42 + 33 + 25)

= 415 x 100

= 41500

a, =12 x ( 45 + 55 )

= 12 x 100 

= 1200

b, = 25 x 4 x 280

= 100 x 280

= 28000

c, = 268 x ( 192 -92)

= 268 x 100

= 26800

Câu 2: Tính bằng cách thuận tiện nhất:

\(a)\)\(12\times45+12\times55\)

\(=\)\(12\times\left(45+55\right)\)

\(=\)\(12\times100\)

\(=\)\(1200\)

\(b)\)\(25\times280\times4\)

\(=\)\(25\times4\times280\)

\(=\)\(100\times280\)

\(=\)\(28000\)

\(c)\)\(268\times192-92\times268\)

\(=\)\(268\times\left(192-92\right)\)

\(=\)\(268\times100\)

\(=\)\(26800\)

Trả lời :

a). 12 x 45 + 12 x 55 = 12 x ( 45 + 55 )

                                  = 12 x 100

                                  = 1200.

b). 25 x 280 x 4 =  280 x ( 25 x 4 )

                          = 280 x 100

                          = 28 000.

c). 268 x 192 - 92 x 268 = 268 x ( 192 - 92 )

                                       = 268 x 100

                                       = 26 800.

Nhớ k cho chị nha , Cảm ơn em.

a) 21/11.22/17.68/63

=21/11.11.2/17.17.4/3.21

=21.11.2.17.4/11.17.3.21

=8/3

b) 5/14.7/13.26/25

=5/2.7.7/13.2.13/5.5

=5.7.2.13/2.7.13.5.5

=1/5