Mixed Operations of Whole Numbers
Mixed operations involve more than one mathematical operation in a single expression. To get the correct answer, we must follow the correct order of operations known as BODMAS.
- B – Brackets
- O – Of (powers and roots)
- D – Division
- M – Multiplication
- A – Addition
- S – Subtraction
Order of Operations (BODMAS)
| Letter | Meaning |
|---|---|
| B | Brackets |
| O | Of |
| D | Division |
| M | Multiplication |
| A | Addition |
| S | Subtraction |
Worked Example
Evaluate:
784 + 930 ÷ 31 − (41 − 5) × 3
Step 1 (Brackets): (41 − 5) = 36
784 + 930 ÷ 31 − 36 × 3
Step 2 (Division): 930 ÷ 31 = 30
784 + 30 − 36 × 3
Step 3 (Multiplication): 36 × 3 = 108
784 + 30 − 108
Step 4 (Addition): 784 + 30 = 814
Step 5 (Subtraction): 814 − 108 = 706
Final Answer: 706
Watch Explanation Video
Interactive Activity: Choose the Next Step
Which operation should be done first in the expression below?
784 + 930 ÷ 31 − (41 − 5) × 3
Mixed Operations of Whole Numbers (BODMAS)
1. Evaluate
1(a) 175 + 25 ÷ 5 + 160 × 2
Answer:
Answer:
25 ÷ 5 = 5
160 × 2 = 320
175 + 5 + 320 = 505
160 × 2 = 320
175 + 5 + 320 = 505
1(b) 514 + (516 − 26) × 5 − 13 × 5
Answer:
Answer:
(516 − 26) = 490
490 × 5 = 2450
13 × 5 = 65
514 + 2450 − 65 = 2899
490 × 5 = 2450
13 × 5 = 65
514 + 2450 − 65 = 2899
1(c) 560 ÷ (245 + 35) + 84 ÷ 21
Answer:
Answer:
245 + 35 = 280
560 ÷ 280 = 2
84 ÷ 21 = 4
2 + 4 = 6
560 ÷ 280 = 2
84 ÷ 21 = 4
2 + 4 = 6
1(d) (415 − 258 + 363 ÷ 121) ÷ 8
Answer:
Answer:
363 ÷ 121 = 3
415 − 258 = 157
157 + 3 = 160
160 ÷ 8 = 20
415 − 258 = 157
157 + 3 = 160
160 ÷ 8 = 20
1(e) 84 ÷ 14 − 15 + 15 − 65 × 10 + 700
Answer:
Answer:
84 ÷ 14 = 6
65 × 10 = 650
6 − 15 + 15 − 650 + 700 = 56
65 × 10 = 650
6 − 15 + 15 − 650 + 700 = 56
Word Problems
2. Kinuthia ordered 15 cartons of chocolates.
Each carton holds 20 boxes and each box has 12 chocolates.
How many chocolates did he order altogether?
Answer:
Answer:
20 × 12 = 240 chocolates per carton
240 × 15 = 3600 chocolates
240 × 15 = 3600 chocolates
3. Mutiso pays Ksh 55 for dinner and Ksh 45 for lunch daily.
Find the total amount he pays for the month of June (30 days).
Answer:
Answer:
Daily cost: 55 + 45 = 100
100 × 30 = Ksh 3000
100 × 30 = Ksh 3000
4. Out of 180,000 Vitamin A tablets,
18,734 tablets are distributed.
How many tablets remain?
Answer:
Answer:
180,000 − 18,734 = 161,266 tablets