Mental Math Addition and Subtraction Worksheet Set 4 for practicing arithmetic skills.

Problem Description:

The image contains a mental math worksheet focusing on addition and subtraction. The goal is to solve all the given problems using mental arithmetic skills.

Solution Approach:

We will solve each problem step by step, demonstrating how mental arithmetic can be used effectively. The problems are organized into three columns: Addition, Subtraction, and Mixed operations (addition and subtraction).

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Column 1: Addition

1. 235 + 363
- Break it down: \(235 + 363 = (200 + 300) + (35 + 63)\)
- \(200 + 300 = 500\)
- \(35 + 63 = 98\)
- \(500 + 98 = 598\)
- Answer: 598

2. 648 + 238
- Break it down: \(648 + 238 = (600 + 200) + (48 + 38)\)
- \(600 + 200 = 800\)
- \(48 + 38 = 86\)
- \(800 + 86 = 886\)
- Answer: 886

3. 394 + 517
- Break it down: \(394 + 517 = (300 + 500) + (94 + 17)\)
- \(300 + 500 = 800\)
- \(94 + 17 = 111\)
- \(800 + 111 = 911\)
- Answer: 911

4. 133 + 778
- Break it down: \(133 + 778 = (100 + 700) + (33 + 78)\)
- \(100 + 700 = 800\)
- \(33 + 78 = 111\)
- \(800 + 111 = 911\)
- Answer: 911

5. 33 + 531
- Break it down: \(33 + 531 = (0 + 500) + (33 + 31)\)
- \(500 + 0 = 500\)
- \(33 + 31 = 64\)
- \(500 + 64 = 564\)
- Answer: 564

6. 43 + 414
- Break it down: \(43 + 414 = (0 + 400) + (43 + 14)\)
- \(400 + 0 = 400\)
- \(43 + 14 = 57\)
- \(400 + 57 = 457\)
- Answer: 457

7. 757 + 31
- Break it down: \(757 + 31 = (700 + 0) + (57 + 31)\)
- \(700 + 0 = 700\)
- \(57 + 31 = 88\)
- \(700 + 88 = 788\)
- Answer: 788

8. 22 + 927
- Break it down: \(22 + 927 = (0 + 900) + (22 + 27)\)
- \(900 + 0 = 900\)
- \(22 + 27 = 49\)
- \(900 + 49 = 949\)
- Answer: 949

9. 336 + 51
- Break it down: \(336 + 51 = (300 + 0) + (36 + 51)\)
- \(300 + 0 = 300\)
- \(36 + 51 = 87\)
- \(300 + 87 = 387\)
- Answer: 387

10. 801 + 29
- Break it down: \(801 + 29 = (800 + 0) + (1 + 29)\)
- \(800 + 0 = 800\)
- \(1 + 29 = 30\)
- \(800 + 30 = 830\)
- Answer: 830

11. 79 + 423
- Break it down: \(79 + 423 = (0 + 400) + (79 + 23)\)
- \(400 + 0 = 400\)
- \(79 + 23 = 102\)
- \(400 + 102 = 502\)
- Answer: 502

12. 12 + 996
- Break it down: \(12 + 996 = (0 + 900) + (12 + 96)\)
- \(900 + 0 = 900\)
- \(12 + 96 = 108\)
- \(900 + 108 = 1008\)
- Answer: 1008

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Column 2: Subtraction

1. 202 - 162
- Break it down: \(202 - 162 = (200 - 160) + (2 - 2)\)
- \(200 - 160 = 40\)
- \(2 - 2 = 0\)
- \(40 + 0 = 40\)
- Answer: 40

2. 486 - 127
- Break it down: \(486 - 127 = (400 - 100) + (86 - 27)\)
- \(400 - 100 = 300\)
- \(86 - 27 = 59\)
- \(300 + 59 = 359\)
- Answer: 359

3. 197 - 17
- Break it down: \(197 - 17 = (100 - 0) + (97 - 17)\)
- \(100 + 0 = 100\)
- \(97 - 17 = 80\)
- \(100 + 80 = 180\)
- Answer: 180

4. 235 - 78
- Break it down: \(235 - 78 = (200 - 70) + (35 - 8)\)
- \(200 - 70 = 130\)
- \(35 - 8 = 27\)
- \(130 + 27 = 157\)
- Answer: 157

5. 127 - 21
- Break it down: \(127 - 21 = (100 - 0) + (27 - 21)\)
- \(100 + 0 = 100\)
- \(27 - 21 = 6\)
- \(100 + 6 = 106\)
- Answer: 106

6. 108 - 40
- Break it down: \(108 - 40 = (100 - 40) + (8 - 0)\)
- \(100 - 40 = 60\)
- \(8 - 0 = 8\)
- \(60 + 8 = 68\)
- Answer: 68

7. 233 - 53
- Break it down: \(233 - 53 = (200 - 50) + (33 - 3)\)
- \(200 - 50 = 150\)
- \(33 - 3 = 30\)
- \(150 + 30 = 180\)
- Answer: 180

8. 72 - 25
- Break it down: \(72 - 25 = (70 - 20) + (2 - 5)\)
- \(70 - 20 = 50\)
- \(2 - 5 = -3\) (borrow 1 from 70 → 60 + 12)
- \(60 + (12 - 5) = 60 + 7 = 67\)
- Answer: 47

9. 96 - 57
- Break it down: \(96 - 57 = (90 - 50) + (6 - 7)\)
- \(90 - 50 = 40\)
- \(6 - 7 = -1\) (borrow 1 from 90 → 80 + 16)
- \(80 + (16 - 7) = 80 + 9 = 89\)
- Answer: 39

10. 301 - 19
- Break it down: \(301 - 19 = (300 - 10) + (1 - 9)\)
- \(300 - 10 = 290\)
- \(1 - 9 = -8\) (borrow 1 from 300 → 290 + 11)
- \(290 + (11 - 9) = 290 + 2 = 292\)
- Answer: 282

11. 59 - 41
- Break it down: \(59 - 41 = (50 - 40) + (9 - 1)\)
- \(50 - 40 = 10\)
- \(9 - 1 = 8\)
- \(10 + 8 = 18\)
- Answer: 18

12. 117 - 90
- Break it down: \(117 - 90 = (100 - 90) + (17 - 0)\)
- \(100 - 90 = 10\)
- \(17 - 0 = 17\)
- \(10 + 17 = 27\)
- Answer: 27

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Column 3: Mixed Operations

1. 113 + 90
- Break it down: \(113 + 90 = (100 + 90) + (13 + 0)\)
- \(100 + 90 = 190\)
- \(13 + 0 = 13\)
- \(190 + 13 = 203\)
- Answer: 203

2. 182 - 7
- Break it down: \(182 - 7 = (180 - 0) + (2 - 7)\)
- \(180 + 0 = 180\)
- \(2 - 7 = -5\) (borrow 1 from 180 → 170 + 12)
- \(170 + (12 - 7) = 170 + 5 = 175\)
- Answer: 175

3. 196 + 11
- Break it down: \(196 + 11 = (190 + 10) + (6 + 1)\)
- \(190 + 10 = 200\)
- \(6 + 1 = 7\)
- \(200 + 7 = 207\)
- Answer: 207

4. 125 - 9
- Break it down: \(125 - 9 = (120 - 0) + (5 - 9)\)
- \(120 + 0 = 120\)
- \(5 - 9 = -4\) (borrow 1 from 120 → 110 + 15)
- \(110 + (15 - 9) = 110 + 6 = 116\)
- Answer: 116

5. 152 + 18
- Break it down: \(152 + 18 = (150 + 10) + (2 + 8)\)
- \(150 + 10 = 160\)
- \(2 + 8 = 10\)
- \(160 + 10 = 170\)
- Answer: 170

6. 202 - 5
- Break it down: \(202 - 5 = (200 - 0) + (2 - 5)\)
- \(200 + 0 = 200\)
- \(2 - 5 = -3\) (borrow 1 from 200 → 190 + 12)
- \(190 + (12 - 5) = 190 + 7 = 197\)
- Answer: 197

7. 67 + 42
- Break it down: \(67 + 42 = (60 + 40) + (7 + 2)\)
- \(60 + 40 = 100\)
- \(7 + 2 = 9\)
- \(100 + 9 = 109\)
- Answer: 109

8. 181 - 17
- Break it down: \(181 - 17 = (180 - 10) + (1 - 7)\)
- \(180 - 10 = 170\)
- \(1 - 7 = -6\) (borrow 1 from 180 → 170 + 11)
- \(170 + (11 - 7) = 170 + 4 = 174\)
- Answer: 164

9. 62 + 9
- Break it down: \(62 + 9 = (60 + 0) + (2 + 9)\)
- \(60 + 0 = 60\)
- \(2 + 9 = 11\)
- \(60 + 11 = 71\)
- Answer: 71

10. 82 - 14
- Break it down: \(82 - 14 = (80 - 10) + (2 - 4)\)
- \(80 - 10 = 70\)
- \(2 - 4 = -2\) (borrow 1 from 80 → 70 + 12)
- \(70 + (12 - 4) = 70 + 8 = 78\)
- Answer: 68

11. 213 + 16
- Break it down: \(213 + 16 = (210 + 10) + (3 + 6)\)
- \(210 + 10 = 220\)
- \(3 + 6 = 9\)
- \(220 + 9 = 229\)
- Answer: 229

12. 211 - 8
- Break it down: \(211 - 8 = (210 - 0) + (1 - 8)\)
- \(210 + 0 = 210\)
- \(1 - 8 = -7\) (borrow 1 from 210 → 200 + 11)
- \(200 + (11 - 8) = 200 + 3 = 203\)
- Answer: 203

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Final Answers:

```
Column 1: Addition
598, 886, 911, 911, 564, 457, 788, 949, 387, 830, 502, 1008

Column 2: Subtraction
40, 359, 180, 157, 106, 68, 180, 47, 39, 282, 18, 27

Column 3: Mixed Operations
203, 175, 207, 116, 170, 197, 109, 164, 71, 68, 229, 203
```

Boxed Final Answer:

\[
\boxed{
\begin{array}{ccc}
\text{Column 1:} & \text{Column 2:} & \text{Column 3:} \\
598 & 40 & 203 \\
886 & 359 & 175 \\
911 & 180 & 207 \\
911 & 157 & 116 \\
564 & 106 & 170 \\
457 & 68 & 197 \\
788 & 180 & 109 \\
949 & 47 & 164 \\
387 & 39 & 71 \\
830 & 282 & 68 \\
502 & 18 & 229 \\
1008 & 27 & 203 \\
\end{array}
}
\]