a, 249 - 25 × 8 + 32 × 4
= 249 - 200 + 9 × 4
= 49 + 36
= 85
b,27 : { 480 : [(513 : 9 + 19 ) + 84 ]}
= 27 : { 480 : [(57 + 19) + 84 ]}
= 27 : { 480 : [76 + 84]}
= 27 : { 480 : 160}
= 27 : 3
= 9
c. 73 × 25 + 28 × 25 - 25
= 73 × 25 + 28 × 25 - 25 × 1
= 25 × (73 + 28 - 1)
= 25 × 100
= 2500
d. 2× 9 × 50 - 890
= (2 × 50) × 9 - 1
= 100 × 9 - 1
= 900 - 1
= 899
a)\(249-25\cdot8+3^2\cdot4\)
\(=249-200+9\cdot4\)
\(=49+36=85\)
b)\(27:\left\{480:\left[\left(513:9+19\right)+84\right]\right\}\)
\(=27:\left\{480:\left[\left(57+19\right)+84\right]\right\}\)
\(=27:\left\{480:\left[76+84\right]\right\}\)
\(=27:\left\{480:160\right\}\)
\(=27:3=9\)
c)\(73\cdot25+28\cdot25-25\)
\(=73\cdot25+28\cdot25-25\cdot1\)
\(=\left(73+28-1\right)\cdot25\)
\(=100\cdot25=2500\)
d)\(2\cdot9\cdot50-89^0\)
\(=2\cdot9\cdot50-1\)
\(=900-1=899\)
a)249 - 25 . 8 + 32.4
= 249 - 200 + 36
= 49 +36
= 85
b)27 : { 480 : [(513:9 + 19 ) +84 ]}
= 27 : { 480 : [76+84]}
= 27: { 480 : 160 }
= 27 : 3
= 9
c) 73.25 +28.25 -25
= 25 . ( 73 +28 - 1)
= 25. 100
= 2500
d)2.9.50 - 890
= 2.9.50 - 1
= 900 - 1
= 899
