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# Exercise 3.2

7th Maths : Term 2 Unit 3 : Algebra : Exercise 3.2 : Fill in the blanks, Say true or false, Find the value of the following, Objective type questions, Text Book Back Exercises Questions with Answers, Solution

Exercise 3.2

1. Fill in the blanks.

(i) Unit digit of 124 × 36 × 980 is 0.

(ii) When the unit digit of the base and its expanded form of that number is 9, then the exponent must be odd power.

2. Match the following: i) 2010 (c) 0

ii) 12111 (d) 1

iii) 44441 (b) 4

iv) 25100 (f) 5

v) 71683 (a) 6

vi) 729725 (e) 9

3. Find the unit digit of expanded form.

(i) 2523

Unit digit of base 25 is 5 and power is 23 (Odd number).

Thus, the unit digit of 2523 is 5.

(ii) 1110

Unit digit of base 11 is 5 and power is 10 (Even number).

Thus, the unit digit of 1110 is 1.

(iii) 4615

Unit digit of base 46 is 6 and power is 15 (Odd number).

Thus, the unit digit of 4615 is 6.

(iv)10012

Unit digit of base 100 is 0 and power is 12 (Even number).

Thus, the unit digit of 10012 is 0.

(v) 2921

Unit digit of base 29 is 9 and power is 21 (Odd number).

Thus, the unit digit of 2921 is 9.

(vi) 1912

Unit digit of base 19 is 9 and power is 12 (Even number).

Thus, the unit digit of 1912 is 1.

(vii) 2425

Unit digit of base 24 is 4 and power is 25(Odd number).

Thus, the unit digit of 2425 is 4.

(viii) 3416

Unit digit of base 34 is 4 and power is 16 (Even number).

Thus, the unit digit of 3416 is 6.

4. Find the unit digit of the following numeric expressions.

(i) 11420 + 11521 + 11622

Unit digit of base 114 is 4 and power is 20 (Even number).

Thus the unit digit of 11420 is 6.

Unit digit of base 115 is 5 and power is 21 (Odd number).

Thus the unit digit of 11521 is 5.

Unit digit of base 116 is 6 and power is 22 (Even number).

Thus the unit digit of 11622 is 6.

6 + 5 + 6 = 17

Unit digit of 17 is 7.

So, Unit digit of 11420 + 11521 +11622 is 7.

(ii) 1000010000 + 1111111111

Unit digit of 10000 is 0 and Power is 10000 (Even number).

So, Unit digit of l000010000 is 0.

Unit digit of 11111 is 1 and power is 11111 (Odd number). So, Unit digit of 1111111111 is 1.

Objective type questions

5. Observe the equation (10 + y)4 = 50625 and find the value of y.

(i) 1

(ii) 5

(iii) 4

(iv) 0

6. The unit digit of (32 × 65)0 is

(i) 2

(ii) 5

(iii) 0

(iv) 1

7. The unit digit of the numeric expression 1071 + 1072 + 1073 is

(i) 0

(ii) 3

(iii) 1

(iv) 2

Exercise 3.2

1. (i) 0 (ii) odd

2. Group A Group B

(i) : (c)

(ii) : (d)

(iii) : (b)

(iv) : (f)

(v) : (a)

(vi) : (e)

3. (i) 5 (ii) 1 (iii) 6 (iv) 0   (v) 9 (vi) 1 (vii) 4 (viii) 6

4. (i) 7 (ii) 1

Objective type questions

5. (ii) 5

6. (iv) 1

7. (i) 0

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7th Maths : Term 2 Unit 3 : Algebra : Exercise 3.2 | Questions with Answers, Solution | Algebra | Term 2 Chapter 3 | 7th Maths