Text Book Back Exercises Questions with Answers, Solution : 4th Maths : Term 3 Unit 2 : Numbers : Exercise 2.7 (multiplication facts by adding partial products mentally)

__Exercise 2.7__

Simplify the following multiplication facts by
adding partial products.

**1.**** 9 x 42 **

**2.**** 3 x 78 **

**3.**** 36 x 12 **

**4.**** 18 x 19**

**5.**** 68 x 31 **

**6.**** 42 x 21 **

**1. 9 x 42 **

42 = 40 + 2

9 x 40 = 360

9 x 2 = 18

360 + 18 = 378

Answer: **378**

**2. 3 x 78 **

78 = 70+8

3 x 70 = 210

3x 8 = 24

210 + 24= 234

Answer: **234**

**3. 36 x12 **

36 = 30 + 6

12 = 10+2

30 x10 = 300

30 x 2 = 60

6 x 10 =60

6 x 2 = 12

300 + 60 +60 +12 = 432

Answer: **432**

**4. 18 x 19 **

18 = 10+8

19 = 10+9

10x10 =100

10 x 9 = 90

8 x10 = 80

8 x 9 = 72

100 +90+80+72=342

Answer: **342**

**5. 68 x 31 **

68 = 60+8

31 = 30+ 1

60 x30 = 1800

60 x 1 = 60

8 x 30 = 240

8 x 1 =8

1800+60+240+8=2108

Answer: **2108 **

**6. 42 x 21**

42 = 40 + 2

21 = 20+1

40 x20 = 800

40 x 1 = 40

2 x20 = 40

2 x 1 = 2

800+40+40+2=882

Answer: **882**

Tags : Numbers | Term 3 Chapter 2 | 4th Maths , 4th Maths : Term 3 Unit 2 : Numbers

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4th Maths : Term 3 Unit 2 : Numbers : Exercise 2.7 (multiplication facts by adding partial products mentally) | Numbers | Term 3 Chapter 2 | 4th Maths

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