Exerciții rezolvate pentru elevii clasei a V-a

1. Ordinea efectuării operaţiilorOrdinea efectuării operaţiilor
cu numere zecimale.cu numere zecimale.
Autor:profesor Pop Peter
Şcoala cu clasele I-VIII nr. 1
Negreşti-Oaş

2. Exerciţiul 1Exerciţiul 1
 Efectuaţi:
a) 20+1,7-6,3=
Rezolvare: 20+1,7-6,30=21,7-6,30=15,4
b) 5,8-2,9+0,37=
Rezolvare: 5,8-2,9+0,37=2,9+0,37=3,27
c) 9,29+2,71-5,4-2,2=
Rezolvare: 9,29+2,71-5,4-2,2=
=12-5,4-2,2=
=6,6-2,2=4,4

3. -continuare--continuare-
 d) 15,24:10:100=
Rezolvare: 15,24:10:100=
=1,524:100=
=0,01524
 e) 8,24∙10:2=
Rezolvare: 8,24∙10:2=82,4:2=41,2
 f) 32,45:5∙20=
Rezolvare: 32,45:5∙20=6,49∙20=129,80

4. --continuare-continuare-
 g) 3,5∙10-27,3=
Rezolvare: 3,5∙10-27,3= 35-27,3=7,7
 h) 4,53∙100-2,7∙23=
Rezolvare: 4,53∙100-2,7∙23=453-2,7∙23=453-62,1=
=390,9
 i) 20-0,47∙5=
Rezolvare: 20-0,47∙5=20-2,35=17,65

5. Alte exerciţii propuse:
 3-2·0,9=
Rezolvare: 3-2·0,9=3-1,8=1,2
 2,5·10-34:10=
Rezolvare: 2,5·10-34:10=25-3,4=21,6
 (5,6+4,4):100=
Rezolvare: (5,6+4,4):100=10:100=0,1
 2,55:3+3:100=
Rezolvare: 2,55:3+3:100=0,85+0,03=0,88
 1,44:144+0,26=
Rezolvare: 1,44:144+0,26=0,01+0,26=0,27

6. -continuare-
 [(6,5+3·1,5):10+0,9]:10+0,8=
Rezolvare: [(6,5+3·1,5):10+0,9]:10+0,8=
=[(6,5+4,5):10+0,9]:10+0,8=
=(11:10+0,9):10+0,8=
=(1,1+0,9):10+0,8=
=2:10+0,8=0,2+0,8=1
 [(10-3,4:2)·10-3]:1000+1=
Rezolvare: [(10-3,4:2)·10-3]:1000+1=
=[(10-1,7)·10-3]:1000+1=
=(8,3·10-3):1000+1=
=(83-3):1000+1=80:1000+1=0,08+1=1,08

7. -continuare-
 (26:40+3,35)·(16:20+2,2)=
Rezolvare: (26:40+3,35)·(16:20+2,2)=
=(0,65+3,35)·(16:20+2,2)=
=4·(16:20+2,2)=
=4·(0,8+2,2)=
=4·3=12
 (28:80+6,65)·(18:60+7,7)=
Rezolvare: (28:80+6,65)·(18:60+7,7)=
=(0,35+6,65)·(18:60+7,7)=
=7·(18:60+7,7)=
=7·(0,3+7,7)=
=7·8=56

8. -continuare-
 (22:40+4,45)∙(12:40+7,7)=
Rezolvare: (22:40+4,45)∙(12:40+7,7)=
=(0,55+4,45)∙(12:40+7,7)=
=5∙(12:40+7,7)=
=5∙(0,3+7,7)=
=5∙8=40
 (32:50+3,36)∙(24:60+6,6)=
Rezolvare: (32:50+3,36)∙(24:60+6,6)=
=(0,64+3,36)∙(24:60+6,6)=
=4∙(24:60+6,6)=
=4∙(0,4+6,6)=
=4∙7=28

9. -continuare-
 (18:40+5,55)∙(28:40+3,3)=
Rezolvare: (18:40+5,55)∙(28:40+3,3)=
=(0,45+5,55)∙(28:40+3,3)=
=6∙(28:40+3,3)=
=6∙(0,7+3,3)=
=6∙4=24
 (26:50+4,48)∙(12:30+6,6)=
Rezolvare: (26:50+4,48)∙(12:30+6,6)=
=(0,52+4,48)∙(12:30+6,6)=
=5∙(12:30+6,6)=
=5∙(0,4+6,6)=
=5∙7=35

10. -continuare-
 (18:40+5,55)∙(28:40+3,3)=
Rezolvare: (18:40+5,55)∙(28:40+3,3)=
=(0,45+5,55)∙(28:40+3,3)=
=6∙(28:40+3,3)=
=6∙(0,7+3,3)=
=6∙4=24
 (26:50+4,48)∙(12:30+6,6)=
Rezolvare: (26:50+4,48)∙(12:30+6,6)=
=(0,52+4,48)∙(12:30+6,6)=
=5∙(12:30+6,6)=
=5∙(0,4+6,6)=
=5∙7=35