Question

Tính bằng cách thuận tiện nhất:

a) 428 x 36 + 64 x 428

b) 512 x 47 - 37 x 512

c) 72 x 4 x 25

d) 4/9 x 3/7 + 5/9 x 3/7

Answer 1

a: =428(36+64)=42800

b: =512(47-37)=5120

c: =72x100=7200

Answer 2

\(428×(36+64)\)

\(=428×100\)

\(=42800\)

 

\(512×(47-37)\)

\(=512×10\)

\(=5120\)

 

\(72×(4×25)\)

\(=72×100\)

\(=7200\)

 

\(\left(\dfrac{4+5}{9}\right)\text{×}\dfrac{3}{7}\)

\(=1\text{×}\dfrac{3}{7}\)

\(=\dfrac{3}{7}\)

Answer 3

a, 428 x 36 + 64 x 428

=  428 x (36 + 64)

=  428 x 100

= 42800

b, 512 x 47 - 37 x 512

=  512 x (47 - 37)

= 512 x 10

= 5120

câu này mik bị lú nên hok lm

d) 4/9 x 3/7 + 5/9 x 3/7

= 3/7 x (4/9 + 5/9)

= 3/7 x 1

= 3/7

 

Answer 4

a: =428(36+64)=42800

b: =512(47-37)=5120

c: =72x100=7200