Sonli va harfli ifodalar

Sonli va harfli ifodalar.
№1
a) (3426+2345)-345=(2345-345)+3426=
=2000+3426=5426
b) (3453+898)-2353=(3453-2353)+898=
=1100+898=1998
d) (6578+1437)-1578=(6578-1578)+1437=
=5000+1437=6437
№2
a) 12478-12378+7934=100+7934=8034
b) 38709+13576-21709=(38709-21709)+
+13576=17000+13576=30576
d) 28676+1111-21776=(28676-21776)+
+1111=6900+1111=8011
e) 41512+13924-23412=(41512-23412)+
+13924=18100+13924=32024
№3
To’g’ri to’rtburchak shaklidagi maktab hovlisining bo’yi 216 m, eni esa bo’yidan 45 m qisqa. Maktab hovlisining perimetrini hisoblang.
Javob:
Maktab hovlisining perimetri 774 m ekan.
Berilgan: Bo’yi__ 216 m
Eni____ ? ,45 m qisqa
Perimetri- ? m
Yechish:
216-45=171 (m) eni
Formula:
P=(bo’yi+eni)∙2
2) P=(216+171) ∙2=774 (m)
№4 “Lacetti” avtomobili massasi 1246 kg, “Cobalt” avtomobili massasi esa 1149 kg. “Cobalt” avtomobili “Lacetti” avtomobilidan necha kilogrammga yengil?Berilgan: “Lacetti” avtomobili-1246 kg“Cobalt” avtomobili-1149 kg ?kg yengilYechish:1246-1149=97 (kg) yengilJavob: “Cobalt” avtomobili “Lacetti” avtomobilidan97 kgga yengil.
“Kim topqir?” o’yini
1) 427 sonining 52 ta kamidan 90 ta ortiq sonni toping.
2) 6714 sonining 714 ta kamidan 500 ta ortiq sonni toping.
3) 100 sonining 22 ta ortig’idan 55 ta ortiq sonni toping.
4) 7458 sonining 64 ta kamidan 90 ta kam sonni toping.
5) 605 sonining 89 ta kamidan 987 ta ortiq sonni toping.
1) (427-52)+90=375+90=465
2) (6714-714)+500=6500
3) (100+22)+55=177
4) (7458-64)-90=
=7394-90=7304
5) (605-89)+987=516+987=1503
Sonli va harfli ifodalar.
6 sm
6 sm Sonlar, arifmetik amallar va qavslardan tuzilgan ifodalar sonli ifodalardeyiladi.
4 sm4 sm
P=2∙(6+4)=2∙6+2∙4=20
6 sm
6 sm Sonlar, harflar, arifmetik amallar va qavslardan tuzilgan ifodalar harfliyoki harfiy ifodalardeyiladi.
a sma sm
P=2∙(6+a)=2∙6+2∙aMasala:
Ishchi 2 soat ishladi. U birinchi soatda 12 dona, 2-soatda esa 1-soatdagidan m dona ko’p detal tayyorladi. Ishchi ikki soatda tayorlagan detallar sonini ifodalaydigan harfli ifoda tuzing.a) m=4 va b) m=8 ga teng bo’ladigan qiymatlarini toping.1-soatda-12 dona d
2-soatda-12+m dona d
Yechish:
12+12+m (dona) detal
a)m=4: 12+12+4=28 (dona) detal
b)m=8: 12+12+8=32 (dona) detal
Javob: Ishchi ikki soatda
m=4: 28 dona,
m=8: 32 dona detal tayyorlagan.
?ta detal
5
№5
Sonli ifodaning qiymatini toping.
13∙5+98=65+98=163127+108:3-24= =127+36-24=13912∙8+98-35= =96+98-35=159
13∙5+98=
127+108:3-24=
12∙8+98-35=5
№6
Harfli ifodaning qiymatini toping.
a)128-31=97 b)39-18=21
128-43=85 124-18=106
128-59=69 215-18=197
d)35+0=35
35+10=45
35+100=135
a)128-b=
b=31; 43; 59
b)b-18=
b=39; 124; 215
c)35+x=
x=0; 10; 100
5
№7
Harfli ifodaning qiymatini toping.
a)(128-12∙3)+(14∙3-18)=116
(128-12∙4)+(14∙4-18)=118
(128-12∙5)+(14∙5-18)=120
b)(30∙4-25)-(20∙4+10)=5
(30∙8-25)-(20∙8+10)=45
(30∙10-25)-(20∙10+10)=65
a) (128-12b)+(14b-18)=
b=3; 4; 5
b)(30y-25)-(20y+10)=
b=4; 8; 10
Yangi mavzuni mustahkamlash
Savollar:
Sonli ifodaning qiymati qanday topiladi?Qanday ifoda sonli ifoda bo’ladi?Sonli ifodaga misollar ayting.Harfli ifoda deb nimaga aytiladi?Harfli ifodada son qiymatni bersak, natija nima chiqadi?Harfli ifodaga misollar keltiring.
Javoblar:
Sonli ifodada amallar belgilangan tartibda bajarilsa, sonli ifodaning qiymati hosil bo’ladi.Sonlar, arifmetik amallar va qavslardan tuzilgan ifodalar sonli ifodalar deyiladi. 15+28-12, 78+26+69,…Sonlar, harflar, arifmetik amallar va qavslardan tuzilgan ifodalar harfli yoki harfiy ifodalar deyiladi. Harfli ifodada son qiymatni bersak, natija son chiqadi.