Question

Tính nhanh

1) 25+91+75+101=

2)41x39-41x9=

3) 710x99+710=

4)17x85+15x17-120=

5) (39x42-37x42):42

6) 120-48-52

7) 23x75+25x23+180

8) 2448 : [ 119- (23-6) ]

Answer 1

1) 25 + 91 + 75 + 101

= (25+75) + (91 + 101)

= 100 + 192

= 292

2) 41 x 39 - 41 x 9

= 41 x (39 - 9)

= 41 x 30

= 1230

3) 710 x 99 + 710

= 710 x 99 + 710 x 1

= 710 x (99 + 1)

= 710 x 100

= 71000

4) 17 x 85 + 15 x 17 - 120

= 17 x (85 + 15) - 120

= 17 x 100 -120

= 1700 -120

= 1580

5) (39 x 42 - 37 x 42) : 42

= 42 x (39 - 37) : 42

= 42 x 2 : 42

= 84 : 42

=2

6) 120 - 48 - 52

= 120 - (48 + 52)

= 120 - 100

= 20

7) 23 x 75 + 25 x 23 + 180

= 23 x (75 + 25) +180

= 23 x (75 + 25) +180

= 23 x 100 + 180

= 2300 +180

=2480

8) 2448 : [119 - (23 - 6)]

= 2448 : (119 - 17)

= 2448 : 102

= 24