146
Masalan: 8х14; s = 8; d = 14; 8 = 10-2; 14 = 10+4; a = 2; b = 4.
sхd = 10х(d-a)-aхb yoki sхd = 10х(s+b) –aхb;
dеmak, 8х14 = 10х (14-2)-2х4 = 10х12-8 = 120-8 = 112 yoki
8х14 = 10х(8+4) -2х4 = 10х12-8 = 120-8 = 112
1)
97 х 125
125 – 100 = 25
+25
97 Х
125
=
-3
(97 + 25) = 122 yoki (125 – 3) = 122
122 х 100 = 12200
3 х 25 = 75
12200 – 75 = 12125
+25
97 Х
125
=
12125
-3
O‗quvchilarga bilimlarini tеkshirish uchun quyidagi mashqlarni taklif
qilish mumkin: 98х128, 92х132, 90х110, 75х135.
Masalan: 1) 98 х 145
145 – 100 = 45
+45
98 Х
145
=
-2
(98 + 45) = 143 yoki (145 – 2) = 143
143 х 100 = 14300
2 х 45 = 90
14300 – 90 = (14300-100)+10=14210
2) 97 х 135
135 – 100 = 35
+35
97 Х
145
=
-3
(97 + 35) = 132 yoki (135 – 3) = 132
132 х 100 = 13200
3 х 35 = 105
13200 – 105 = (13200-100)-5=13095
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