Simplify the expression: (−14) + (512).
Answer: −312 + 512 = 212 = 16
Step-by-step solution
Idea: Make the denominators equal (LCM of 4 and 12 is 12), add the numerators, then reduce.
- LCM of 4 and 12 is 12, so −14 = −312.½ mark
- −312 + 512 = −3 + 512 = 212.1 mark
- Divide top and bottom by 2: 16.½ mark
(−1/4) + (5/12) = 1/6
Check: −0.25 + 0.4167 = 0.1667 = 16 ✓.
Answer to write in the exam
(−14) + 512 = −312 + 512
= 212
∴ = 16
Common mistakes that cost marks
- Giving −16: −3 + 5 = +2, so the answer is positive.
- Adding across: −1 + 54 + 12 = 416.
- Stopping at 212 without simplifying.
How this can come in the exam
MCQ (1 mark)
(−56) + 718 =
- 49
- −49
- 224
- −19
Show answer
(B) −49
−1518 + 718 = −818 = −49.
Short answer (2 marks)
Simplify (−29) + 56 + (−13).
Show answer
LCM 18: −418 + 1518 − 618 (1 mark) = 518 (1 mark).Try one yourself
Simplify (−310) + 715.
Show answer
−930 + 1430 = 16.
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