arpitjain wrote:
Which of the following expressions are equal to 21 ?
Indicate all correct answer choices.
A) 3 + 7 × 2 + 12 ÷ (2 + 1)
B) 1 + (3 ÷ 2) × 10 + 1
C) 7 – 3 × 3 + (5 + 4)
D) 4 × (3 + 2) – (3 – 4)
E) (2 + 6) × 1 + 3 – 6 × 4 + 1
We'll to use either BEDMAS or PEMDAS (same thing) to determine the
order of operationsA) 3 + 7 × 2 + 12 ÷ (2 + 1) = 3 + 7 × 2 + 12 ÷
3= 3 +
14 + 12 ÷ 3
= 3 + 14 +
4=
17 + 4
=
21B) 1 + (3 ÷ 2) × 10 + 1 = 1 +
1.5 × 10 + 1
= 1 +
15 + 1
= 16 + 1
= 17
C) 7 – 3 × 3 + (5 + 4) = 7 – 3 × 3 +
9= 7 –
9 + 9
=
-2 + 9
= 7
D) 4 × (3 + 2) – (3 – 4) = 4 ×
5 – (
-1)
=
20 - (-1)
=
21E) (2 + 6) × 1 + 3 – 6 × 4 + 1 =
8 × 1 + 3 – 6 × 4 + 1
=
8 + 3 – 6 × 4 + 1
= 8 + 3 –
24 + 1
=
11 – 24 + 1
=
-13 + 1
= -12
Answer: A and D
Cheers,
Brent