RBSE Solutions Class 6 Maths Chapter 7 Vedic Mathematics Exercise 7.2

Question 1. Subtract by the formula of eknunen poorven & “Param mitra ank”.
(i) 75 - 27
(ii) 84 - 56
(iii) 435 - 146
(iv) 840 - 573
(v) 75 Rs 40 p - 56 Rs 73 p
(vi) 134 m 40 cm - 65 m 85 cm
(vii) 235 kg 125 gm - 79 kg 238 gm
Answer: The "eknunen poorven" and "param mitra ank" method is a Vedic mathematics technique for subtraction, especially useful when a digit in the minuend is smaller than the corresponding digit in the subtrahend. It involves using complementary digits and reducing the previous digit.
(i) For \( 75 - 27 \):
    First, consider the rightmost digits: \( 5 - 7 \). Since 5 is smaller than 7, we take the complementary digit of 7 (which is 3, because \( 10 - 7 = 3 \)). Add this complementary digit to 5: \( 5 + 3 = 8 \). Write 8 as the unit's digit of the answer.
    Next, apply "eknunen poorven" to the digit 7 in the tens place of 75. This means reduce it by one, so 7 becomes 6. Now, subtract the tens digit of the subtrahend (2) from this new digit (6): \( 6 - 2 = 4 \). Write 4 as the ten's digit of the answer.
    Thus, \( 75 - 27 = 48 \).

(ii) For \( 84 - 56 \):
    First, consider the rightmost digits: \( 4 - 6 \). Since 4 is smaller than 6, we take the complementary digit of 6 (which is 4, because \( 10 - 6 = 4 \)). Add this complementary digit to 4: \( 4 + 4 = 8 \). Write 8 as the unit's digit of the answer.
    Next, apply "eknunen poorven" to the digit 8 in the tens place of 84. This means reduce it by one, so 8 becomes 7. Now, subtract the tens digit of the subtrahend (5) from this new digit (7): \( 7 - 5 = 2 \). Write 2 as the ten's digit of the answer.
    Thus, \( 84 - 56 = 28 \).

(iii) For \( 435 - 146 \):
    Units digit: \( 5 - 6 \). 5 is smaller than 6. Complementary digit of 6 is 4. Add to 5: \( 5 + 4 = 9 \). Write 9.
    Tens digit (after poorven): Apply "eknunen poorven" to 3 (from 435), so 3 becomes 2. Now subtract 4 (from 146) from this 2: \( 2 - 4 \). 2 is smaller than 4. Complementary digit of 4 is 6. Add to 2: \( 2 + 6 = 8 \). Write 8.
    Hundreds digit (after poorven): Apply "eknunen poorven" to 4 (from 435), so 4 becomes 3. Now subtract 1 (from 146) from this 3: \( 3 - 1 = 2 \). Write 2.
    Thus, \( 435 - 146 = 289 \).

(iv) For \( 840 - 573 \):
    Units digit: \( 0 - 3 \). 0 is smaller than 3. Complementary digit of 3 is 7. Add to 0: \( 0 + 7 = 7 \). Write 7.
    Tens digit (after poorven): Apply "eknunen poorven" to 4 (from 840), so 4 becomes 3. Now subtract 7 (from 573) from this 3: \( 3 - 7 \). 3 is smaller than 7. Complementary digit of 7 is 3. Add to 3: \( 3 + 3 = 6 \). Write 6.
    Hundreds digit (after poorven): Apply "eknunen poorven" to 8 (from 840), so 8 becomes 7. Now subtract 5 (from 573) from this 7: \( 7 - 5 = 2 \). Write 2.
    Thus, \( 840 - 573 = 267 \).

(v) For 75 Rs 40 p - 56 Rs 73 p:
    Paise (p) column: \( 40 - 73 \). Since 40 is smaller than 73, we need to convert 1 Rupee from the Rs column to 100 paise and add it to 40. This makes it \( 140 - 73 \). Use the method for \( 140 - 73 \):
        Units digit: \( 0 - 3 \). Complementary digit of 3 is 7. Add to 0: \( 0 + 7 = 7 \). Write 7.
        Tens digit (after poorven): Apply "eknunen poorven" to 4 (from 140), so 4 becomes 3. Now subtract 7 (from 73) from this 3: \( 3 - 7 \). 3 is smaller than 7. Complementary digit of 7 is 3. Add to 3: \( 3 + 3 = 6 \). Write 6.
        Thus, \( 140 - 73 = 67 \). So, 67 paise.
    Rupees (Rs) column (after poorven): Apply "eknunen poorven" to 75 (from 75 Rs), so 75 becomes 74. Now subtract 56 from 74:
        Units digit: \( 4 - 6 \). Complementary digit of 6 is 4. Add to 4: \( 4 + 4 = 8 \). Write 8.
        Tens digit (after poorven): Apply "eknunen poorven" to 7 (from 74), so 7 becomes 6. Now subtract 5 (from 56) from this 6: \( 6 - 5 = 1 \). Write 1.
        Thus, \( 74 - 56 = 18 \). So, 18 Rs.
    Therefore, \( 75 \text{ Rs } 40 \text{ p} - 56 \text{ Rs } 73 \text{ p} = 18 \text{ Rs } 67 \text{ p} \).

(vi) For 134 m 40 cm - 65 m 85 cm:
    Centimeter (cm) column: \( 40 - 85 \). Since 40 is smaller than 85, we need to convert 1 meter from the m column to 100 cm and add it to 40. This makes it \( 140 - 85 \). Use the method for \( 140 - 85 \):
        Units digit: \( 0 - 5 \). Complementary digit of 5 is 5. Add to 0: \( 0 + 5 = 5 \). Write 5.
        Tens digit (after poorven): Apply "eknunen poorven" to 4 (from 140), so 4 becomes 3. Now subtract 8 (from 85) from this 3: \( 3 - 8 \). 3 is smaller than 8. Complementary digit of 8 is 2. Add to 3: \( 3 + 2 = 5 \). Write 5.
        Thus, \( 140 - 85 = 55 \). So, 55 cm.
    Meter (m) column (after poorven): Apply "eknunen poorven" to 134 (from 134 m), so 134 becomes 133. Now subtract 65 from 133:
        Units digit: \( 3 - 5 \). Complementary digit of 5 is 5. Add to 3: \( 3 + 5 = 8 \). Write 8.
        Tens digit (after poorven): Apply "eknunen poorven" to 3 (from 13), so 3 becomes 2. Now subtract 6 (from 65) from this 2: \( 2 - 6 \). 2 is smaller than 6. Complementary digit of 6 is 4. Add to 2: \( 2 + 4 = 6 \). Write 6.
        Hundreds digit (after poorven): Apply "eknunen poorven" to 1 (from 13), so 1 becomes 0. Subtract 0 from 0: \( 0 - 0 = 0 \). Write 0.
        Thus, \( 133 - 65 = 68 \). So, 68 m.
    Therefore, \( 134 \text{ m } 40 \text{ cm} - 65 \text{ m } 85 \text{ cm} = 68 \text{ m } 55 \text{ cm} \).

(vii) For 235 kg 125 gm - 79 kg 238 gm:
    Gram (gm) column: \( 125 - 238 \). Since 125 is smaller than 238, we need to convert 1 kg from the kg column to 1000 gm and add it to 125. This makes it \( 1125 - 238 \). Use the method for \( 1125 - 238 \):
        Units digit: \( 5 - 8 \). Complementary digit of 8 is 2. Add to 5: \( 5 + 2 = 7 \). Write 7.
        Tens digit (after poorven): Apply "eknunen poorven" to 2 (from 12), so 2 becomes 1. Now subtract 3 (from 238) from this 1: \( 1 - 3 \). 1 is smaller than 3. Complementary digit of 3 is 7. Add to 1: \( 1 + 7 = 8 \). Write 8.
        Hundreds digit (after poorven): Apply "eknunen poorven" to 1 (from 11), so 1 becomes 0. Now subtract 2 (from 238) from this 0: \( 0 - 2 \). 0 is smaller than 2. Complementary digit of 2 is 8. Add to 0: \( 0 + 8 = 8 \). Write 8.
        Thousands digit (after poorven): Apply "eknunen poorven" to 1 (from 11), so 1 becomes 0. Subtract 0 from 0: \( 0 - 0 = 0 \). Write 0.
        Thus, \( 1125 - 238 = 887 \). So, 887 gm.
    Kilogram (kg) column (after poorven): Apply "eknunen poorven" to 235 (from 235 kg), so 235 becomes 234. Now subtract 79 from 234:
        Units digit: \( 4 - 9 \). Complementary digit of 9 is 1. Add to 4: \( 4 + 1 = 5 \). Write 5.
        Tens digit (after poorven): Apply "eknunen poorven" to 3 (from 23), so 3 becomes 2. Now subtract 7 (from 79) from this 2: \( 2 - 7 \). 2 is smaller than 7. Complementary digit of 7 is 3. Add to 2: \( 2 + 3 = 5 \). Write 5.
        Hundreds digit (after poorven): Apply "eknunen poorven" to 2 (from 23), so 2 becomes 1. Subtract 0 from 1: \( 1 - 0 = 1 \). Write 1.
        Thus, \( 234 - 79 = 155 \). So, 155 kg.
    Therefore, \( 235 \text{ kg } 125 \text{ gm} - 79 \text{ kg } 238 \text{ gm} = 155 \text{ kg } 887 \text{ gm} \).
In simple words: When a digit on top is smaller than the digit below it, you use a "friendly number" (complementary digit) to help. You add this friendly number to the top digit and then reduce the digit to its left by one. Keep doing this for each column to find the final answer. This method makes subtraction easier, especially when you need to borrow.

🎯 Exam Tip: Always remember to apply the "eknunen poorven" (reduce by one) rule to the digit to the left in the minuend after using a complementary digit. Also, ensure you convert units correctly (e.g., 1 Rupee = 100 paise, 1 kg = 1000 gm) when dealing with combined units.