Question

Tinhs hợp lí :
a, 75 x 20,9 + 5^2 x 20,9
b, 86 x 15 + 150 x 1,4
c, 93 x 32 + 14 x 16
d, 98, 6 x 199 - 990 x 9,86
e, -8 x 40 + 2 x 108 + 24
f, 993 x 98 + 21 x 331 - 50 x 99,3

Answer 1

a) \(75.20,9+5^2.20,9\)

\(=20,9\left(75+5^2\right)\)

\(=20,9\left(75+25\right)\)

\(=20,9.100\)

\(=2090\)

b) \(86.15+150.1,4\)

\(=15\left(86+10.1,4\right)\)

\(=15\left(86+14\right)=15.100=1500\)

c) \(93.32+14.16\)

\(=16\left(93.2+14\right)\)

\(=16\left(186+14\right)=16.200=3200\)

d) \(98,6.199-990.9,86\)

\(=9,86\left(10.199-990\right)=9,86\left(1990-990\right)\)

\(=9,86.1000=9860\)

e) \(-8.40+2.108+24\)

\(=-8.40+2.4.27+8.3\)

\(=-8\left(40-27-3\right)=-8.10=-80\)