Question

Tính nhanh:

a,9.24.25

b,12.125.5

c,64.125.875

d,425.7.4 - 170 .60

e,8.9.14 +6.7 .12+19.4.18

Answer 1

a) 9 . 24 . 25

= 9 . 600

= 5400

b) 12 . 125 . 5 = (12 . 5) . 125

= 60 . 125 =7500

c) 64 . 125 . 875= 8000 . 875 = 7000000

d) 425 . 7 . 4 - 170 . 60 = 1700 . 7 - 170 . 60

= 170 . (10 . 7) - 170 . 60

= 170 . 70 - 170 . 60

= 170 . (70 - 60)

= 170 . 10 = 1700

Answer 2

a, 9 . 24. 25 = 9. ( 25.24 ) = 9 . 600 = 5400

b, 12.125.5 = 1500.5 = 7500

c , 64 . 125 . 5 = ( 64 . 125 ) . 5 = 8000 . 5 = 40000

d, 425 . 7 . 4 - 170 . 60 = 1700 . 7 - 10200 = 11900 - 10200 = 1700

e , 8.9.14 + 6 . 7 .13 + 19 . 4 . 18 = 1008 + 546 + 1368 = 2922

Answer 3

\(8.9.14+6.7.12+19.4.18\)

\(=8.3.3.14+42.12+19.2.2.18\)

\(=24.42+42.12+38.36\)

\(=42.\left(24+12\right)+38.36\)

\(=42.36+38.36\)

\(=36.\left(42+38\right)\)

\(=36.90\)

\(=3240\)