We will discuss here about the combination of addition and subtraction.
To show the problems involving both addition and subtraction, we first group all the numbers with ‘+’ and ‘-‘ signs. We find the sum of the numbers with ‘+’ sign and similarly the sum of all the numbers with ‘-‘ sign and then find the difference. If there is no sign before a number it means ‘+’ sign.
The rules which can be used to solve the sums involving addition (+) and subtraction (-) together are:
I: First add and then subtract,
II: Solve the numbers enclosed in the brackets and then solve further.
To solve the questions which involve both addition and subtraction, we first add and then subtract the required number from the sum.
1. Let us consider 11 + 26 - 12.
Step I: First add 11 and 26. The sum of 11 and 26 is 37.
37 - 12 = 25 |
Answer: 11 + 26 - 12 = 25
2. Let us take another example. A shopkeeper has 90 oranges. He sold 51 oranges on Monday and 25 oranges on Tuesday. How many oranges are left with him?
|
T O |
Oranges sold on Monday |
5 1 |
Oranges sold on Tuesday |
+ 2 5 |
Total oranges sold |
7 6 |
Oranges left = Total Oranges - Oranges Sold
|
T O |
Total Oranges |
9 0 |
Oranges Sold |
- 7 6 |
Number of Oranges Left |
1 4 |
Solved Example Involving Addition (+) and Subtraction (-) ogether:
1. Solve 3252 - 1802 + 2610
Solution:
3 2 5 2
+ 2 6 1 0
5 8 6 2
Now
5 8 6 2
- 1 8 0 2
4 0 6 0
2. Find the solution to (7259 - 5369) + 2156
Solution:
6 11 15
7 2 5 9
- 5 3 6 9
1 8 9 0
Now
1 1
1 8 9 0
+ 2 1 5 6
4 0 4 6
3. Subtract 4926 from the sum of 3051 and 4257
Solution:
Sum of 3051 and 4257
1
3 0 5 1
+ 4 2 5 7
7 3 0 8
Now, subtract 4926 from 7308
6 12 10
7 3 0 8
- 4 9 2 6
2 3 8 2
4. Solve 481 + 356 – 168.
Solution:
Step I: Add the numbers with ‘+’ sign.
Step II: Subtract the number with ‘-‘ sign from the sum of the numbers with ‘+’ sign.
Therefore, 481 + 356 – 168 = 669
Addition and Subtraction Together
5. 4235 - 4732 + 3543
Th H T O 4 2 3 5 + 3 5 4 3 7 7 7 8 |
Step I: First add 4235 + 3543 |
Th H T O 7 7 7 8 - 4 7 3 2 3 4 4 6 |
Step II: Subtract 4732 from result of step I i.e., 7778 |
Remember:
● If there is no +/- sign before numbers then always assume + sign.
● First add and then subtract the digit.
● Subtract the digits which face '-' sign.
Word Problems on Addition and Subtraction Together:
6. Daniel has 478 chocolate cookies and 245 chocolate chip cookies. He distributed 323 cookies among his friends. How many cookies were left with him?
Solution:
Chocolate cookies = 478
Chocolate chip cookies = 245
Step I: Addition
Total number of cookies = 478 + 245 = 753
Cookies Distributed = 323
Step II: Subtraction
Cookies left with Daniel = 753 - 323 = 430
Questions and Answers on Addition and Subtraction Together:
1. Fill in the blanks -
(i) 5555 - 3213 + 4235
Th H T O 5 5 5 5 + 4 2 3 5
|
Th H T O _ _ _ _ - 3 2 1 3
|
(ii) 5362 - 4141 + 2222
Th H T O 5 3 6 2 + 2 2 2 2
|
Th H T O _ _ _ _ -
|
(iii) 6247 + 2431 - 5132
Th H T O 6 2 4 7 + 2 4 3 1
|
Th H T O _ _ _ _ - 5 1 3 2
|
(iv) 4321 + 1541 - 3323
Th H T O 4 3 2 1 + 1 5 4 1
|
Th H T O _ _ _ _ -
|
Answer:
1. (i)
Th H T O 5 5 5 5 + 4 2 3 5 9 7 9 0 |
Th H T O 9 7 9 0 - 3 2 1 3 6 5 7 7 |
(ii)
Th H T O 5 3 6 2 + 2 2 2 2 7 5 8 4 |
Th H T O 7 5 8 4 - 4 1 4 1 3 4 4 3 |
(iii)
Th H T O 6 2 4 7 + 2 4 3 1 8 6 7 8 |
Th H T O 8 6 7 8 - 5 1 3 2 3 5 4 6 |
(iv)
Th H T O 4 3 2 1 + 1 5 4 1 5 8 6 2 |
Th H T O 5 8 6 2 - 3 3 2 3 2 5 3 9 |
2. Do these sums in your notebook -
(i) 2222 + 3333 - 1111
(ii) 3122 + 4212 - 2112
(iii) 4364 + 3213 - 6243
(iv) 5154 + 2343 - 4265
(v) 8546 - 6324 - 2112
(vi) 9798 - 7656 + 7554
(vii) 8746 - 5534 + 2465
(viii) 3778 - 2563 + 4672
(ix) 2432 + 1342 - 1121
(x) 4365 + 434 - 1213
(xi) 3794 + 1213 - 2505
(xii) 7811 - 1222 + 234
(xiii) 5234 + 3259 - 4172
(xiv) 3777 + 2111 - 4352
(xv) 2725 + 1234 - 786
(xvi) 2575 + 2430 - 1225
(xvii) 7250 - 5450 + 3550
(xviii) 2775 + 1465 - 1275
(xix) 2537 - 2425 + 1212
(xx) 4533 - 2322 + 289
Answer:
2. (i) 4444
(ii) 5222
(iii) 1334
(iv) 3232
(v) 110
(vi) 9696
(vii) 5677
(viii) 5887
(ix) 2653
(x) 3586
(xi) 2502
(xii) 6823
(xiii) 4321
(xiv) 1536
(xv) 3173
(xvi) 3780
(xvii) 5350
(xviii) 2965
(xix) 1324
(xx) 2500
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