অনুশীলনীঃ 1.2
1. পূৰণফল নিৰ্ণয় কৰা-
(i) 5×(-2).
Ans= 5 × (-2)
= -10
(ii) (-3)×7
Ans= (-3) × 7
= -21
(iii) (-4) × (-3)
Ans= (-4) × (-3)
= 12
(iv) (-129) × (-1)
Ans= (-129) × (-1)
= 129
(v)(-12) × 0 × (-17)
Ans= (-12) × 0 ×(-17)
= 0
(vi) (-22) × (-11) × 10
Ans= (-22) × (-11) × 10
= 2420
(vii) 13 × (-5) × (-3)
Ans= 13 × (-5) × (-3)
= 195
(viii)(-27) × (-31) × (-2)
Ans= (-27) × (-31) × (-2)
= 1674
(ix) (-3) × (-1) ×(-2) × 5
Ans= (-3) × (-1) × (-2) × 5
= 3 × (-10)
= -30
2. সত্যাসত্য বিচাৰ কৰা-
(i) 27 × {(-5+10)}= 27 × (-5) + 27 × 10
Ans= 27 × {(-5+10)}= 27 × (-5) + 27 × 10
⇒27 × 5 = (-135) + 270
⇒ 135 = 135
উত্তৰ- সত্য।
(ii) (-25) × {(-16) + (-24)}= (-25) × (-16) × (-24)
Ans= (-25) × {(-16) + (-24)} = (-25) × (-16) × (-24)
⇒(-25) × (-40) = (-25) × 384
⇒ 1000 = 9600
উত্তৰ- অসত্য।
(iii) a- (-b)= a+b, য'ত a = (-75), b = (-20)
Ans= a- (-b) = a+b
⇒ (-75)- {-(-20)} = (-75) + (-20)
⇒(-75) - 20 = (-75) -20
⇒ -95 = -95
উত্তৰ- সত্য।
3. (i) যিকোনো দুটা অখণ্ড সংখ্যাৰ পূৰণফল -33। তাৰে এটা 11 হলে আনটো কিমান?
Ans- দিয়া আছে, দুটা অখণ্ড সংখ্য়াৰ পূৰণফল = -33
তাৰে এটা অখণ্ড সংখ্যাৰ হ'ল = 11
আনটো সংখ্য়া হ'ল = x (ধৰো)
প্ৰশ্নমতে,
11× x = -33
⇒ x = -33 ፥ 11
⇒ x = -3
∴ আনটো সংখ্যা হ'ল = -3।
(ii) যিকোনো দুটা অখণ্ড সংখ্যাৰ পূৰণফল 51। তাৰে এটা -1 হলে অনটো কিমান?
Ans- দিয়া আছে, সংখ্য়া দুটাৰ পূৰণফল = 51
এটা সংখ্যা হ'ল = -1
আনটো সংখ্য়া হ'ব = x (ধৰো)
প্ৰশ্নমতে,
(-1) × x = 51
⇒ x = 51 ፥ (-1)
x = -51
∴ আনটো সংখ্য়া হ'ল = -51।
(iii) যিকোনো অখণ্ড সংখ্যা a ৰ বাবে (-1 × a) ৰ মান কিমান হব?
Ans- অখণ্ড সংখ্যা a ৰ মান হ'ব= -1× a = -a।
4. উপযুক্ত বিধি প্ৰয়োগ কৰি পূৰণফল নিৰ্ণয় কৰা-
(i) 125 × (-54) × 8
Ans- 125 × (-54) × 8
= (125 × 8) × (54)
= 1000 × 54
= 54,000
(ii) (-25) × (-97) × 4
Ans- (-25) × (-97) × 4
= {(-25) × 4} × (-97)
= (-100) × (-97)
= 9700
(iii) (-27) × (-33)
Ans- (-27) × (-33)
= (-27) × {-(30 + 3)}
= (-27) × (-30) + (-27) × (-3)
= 810 + 81
= 891
(iv) 25 × (-58) + (-58) × (-35)
Ans- 25 × (-58) + (-58) × (-35)
= (-58) × {25 + (-35)}
= (-58) × (-10)
= 580
(v) 15 × (-25) × (-4) × (-10)
Ans-
(vi) (-57) × (-19) × 57
Ans- (-57) × (-19) × 57
= {(-57) × (-19)} × 57
= 1083 × 57
= 61,731
5. বিনিময় আৰু সহযোগ বিধিৰ সহায়ত মান নিৰ্ণয় কৰাঃ
(i) 125 × (54) × 8
Ans- 125 × (54) × 8
(ii) (-25) × 75 × 8 × (-4)
Ans- (-25) × 75 × 8 × (-4)
= {(-25) × (-4)} × (75 × 8)
= 100 × 600
= 60,000
(iii) 225 × 67 × 3
Ans- 225 × 67 × 3
= 225 × (67 × 3)
= 225 × 201
= 45,225
6.বিতৰণ বিধিৰ সহায়ত মান নিৰ্ণয় কৰাঃ
(i) 172× 25 + 172 × 35
Ans- 172 × 25 + 172 × 35
= 172 × (25 + 35)
= 172 × 60
= 10,320
(ii) 159 × 82 + 159 × 16 + 159 × 2
Ans- 159 × 82 + 159 × 16 + 159 × 2
= 159 × (82 + 16 + 2)
= 159 × 100
= 15,900
(iii) 67 × 78 + 67 × (-43) + 67 × (-25)
Ans- 67 × 78 + 67 × (-43) + 67 × (-25)
= 67 × {78 + (-43) + (-25)}
= 67 × {78 + (-68)}
= 67 × 10
= 670
(iv) 999 × 99 + 99
Ans- 999 × 99 + 99
= 99 × (999+ 1)
= 99 × 1000
= 99,000
(v) 58 × 47 +94
Ans- 58 × 47 + 94
= 58 × 47 + (2 × 47)
= 47 × (58 + 2)
= 47 × 60
= 2,820
7. শুদ্ধ অশুদ্ধ বিচাৰ কৰাঃ
(i) (-7) × 15 × (-4) = (-7) × 15 + (-7) × (-4)
Ans- (-7) × 15 × (-4) = (-7) × 15 + (-7) × (-4)
⇒ (-7) × (-60) = (-105) + 28
⇒ 420 = 2,940
উত্তৰ- অশুদ্ধ।
(ii) (-6) × 23 × (-2) = (-2) × (-6) × 23
Ans- (-6) × 23 × (-2) = (-2) × (-6) × 23
⇒ (-6) × (-46) = 12 × 23
⇒ 276 = 276
উত্তৰ - শুদ্ধ।
(iii) (-5) × {(-3) × 2}= {(-5) × (-3)} × 2
Ans- (-5) × {(-3) × 2} = { (-5) × (-3)} × 2
⇒(-5) × (-6) = 15 × 2
⇒ 30 = 30
উত্তৰ - শুদ্ধ।
(iv) (-175) × (-1) = -175
Ans- (-175) × (-1) = -175
⇒ 175 = -175
উত্তৰ- অশুদ্ধ।
(v) (-25) } × (-4) × 0 = 1000
Ans- (-25) × (-4) × 0 = 1000
⇒(-25) × 0 = 1000
⇒ 0 = 1000
উত্তৰ- অশুদ্ধ।
Answer by - Punya Hazarika
Post Id: DABP000812
