## Mathematical operation and symbol notation

#### Mathematical operation and symbol notation

1. If '-' stands for '÷', '+' stands for 'x', '÷' stands for '-' and 'x' stands for '+', find out which one is correct?
1. 49 + 7 - 3 x 5 ÷ 8 = 20
2. 49 - 7 + 3 ÷ 5 x 8 = 24
3. 49 x 7 + 3 ÷ 5 - 8 = 16
4. 49 ÷ 7 x 3 + 5 - 8 = 26

1. Try All option one by one

##### Correct Option: B

From option (b),
49 - 7 + 3 ÷ 5 x 8 = 24
Change the sign, as per the question,
49 ÷ 7 x 3 - 5 + 8 = 24
⇒ 7 x 3 - 5 + 8 = 24
⇒ 21 - 5 + 8 = 24
∴ 24 = 24

1. Select the correct combination of mathematical signs to replace '*' signs and to balance the following equation.
6 * 4 * 12 * 12
1. ÷, -, =
2. +, -, ÷
3. =, -, ÷
4. x, -, =

1. Try all option one by one.

##### Correct Option: D

6 * 4 * 12 * 12
From option (d),
6 x 4 - 12 = 12
⇒ 12 = 12

1. If 'x' stands for '+', '<' for '-', '+' for ' ÷', '>' for 'x', '-' for '=', ' ÷' for '>' and '=' for '<', then state which of the following is true ?
1. 3 x 4 > 2 - 9 + 3 < 3
2. 5 x 3 < 7 ÷ 8 + 4 x 1
3. 5 > 2 + 2 = 10 < 4 x 8
4. 3 x 2 < 4 ÷ 16 > 2 + 4

1. Using the proper symbols in question and solve all option one by one.

##### Correct Option: C

Using the proper symbols in (c), we get
5 x 2 ÷ 2 < 10 - 4 + 8
⇒ 5 x 1 < 18 - 4 ⇒ 5 < 14
which is true.

1. If '-' stands for '÷', '+' stands for '-', '÷' stands for 'x', 'x' stands for '+', then which one of the following equation is correct?
1. 70 - 2 + 4 ÷ 5 x 6 = 44
2. 70 - 2 + 4 ÷ 5 x 6 = 21
3. 70 - 2 + 4 ÷ 5 x 6 = 341
4. 70 - 2 + 4 ÷ 5 x 6 = 96

1. Change the proper sign according to question and try all option one by one by applying the BODMAS Rule.

##### Correct Option: B

Change the proper sign according to question and try all option one by one by applying the BODMAS Rule.
'-' ⇒ ÷
'+' ⇒ '-'
÷ ⇒ 'x'
'x' ⇒ '+'
∴ 70 ÷ 2 - 4 x 5 + 6 = 21
⇒ 35 - 20 + 6 = 21
⇒ 15 + 6 = 21
⇒ 21 = 21

1. If '+' means '÷', '-' means '+', 'x' means '-' and '÷' means 'x', then what is the value of 24 ÷ 12 - 18 + 9 ?
1. -25
2. 0.72
3. 15.30
4. 290

1. Using the proper symbols, we have
24 ÷ 12 - 8 + 9
Now Apply the BODMAS Rule

##### Correct Option: D

Using the proper symbols, we have
24 ÷ 12 - 8 + 9
Now Apply the BODMAS Rule,
= 24 x 12 + 18 ÷ 9
= 288 + 2 = 290