Matematika

1. feladat
a) 1568:56-4*7 = 28-28 = 0
b) (-54)*(-2)-(-12)*(+9) = +108-(-108) =108+108 = 216
c) (2/3+3/4)*6/17-2/3:4/3 = (8/12+9/12)*6/17-2/3:4/3 = 17/12*6/17-2/3:4/3 = 1/2-2/3:4/3 = 1/2-2/3*3/4 = 1/2-1/2 = 0
d) 10,655*8+(40,56-25,8) = 10,655*8+14,76 = 85,24+14,76 = 100

2. feladat
a) 935 km 710 m 50 cm = 935710,5 m = 935,7105 km
b) 5 t-148 kg = 485200 dkg
c) 720 min = 0,5 nap
d) 5 m2+3 dm2 = 503 dm2 = 50300 cm2
e) 3 m3 = 3000000 cm3 = 3000 dm3

3. feladat
16 fiú és 10 lány, vagyis 26 gyerek jár az osztályba. A testnevelés órán 16 fiú és 7 lány volt.

4. feladat
7(x-9)+1 = 4(3-x)+3
7x-63+1 = 12-4x+3
7x-62 = 15-4x /+4x
11x-62 = 15 /+62
11x = 77 / :11
x = 7

Ell.:
Jo.: 7(x-9) = 7(7-9)+1 = 7*(-2)+1 = -14+1 = -13
Bo.: 4(3-x) = 4(3-7)+3 = 4*(-4)+3 = -16+3 = -13
Jo=Bo

5. feladat
a= 1 cm
b= 2 cm
c= 3 cm
a+b+c=1+2+3=6
A = ?
V = ?
A = (a*b+a*c+b*c)*2 = (1*2+1*3+2*3)*2 = (2+3+6)*2 = 11*2 = 22
A = 22 cm2
V = a*b*c = 1*2*3 = 6
V = 6 cm3