## Mathematical operation and symbol notation

#### Mathematical operation and symbol notation

Direction: Correct the following equations by interchanging the two signs.

1. 16 - 21 ÷ 7 x 6 + 3 = 31

1. Lets try all options one by one.

##### Correct Option: B

If we interchange of signs '+' and 'x', then the equation changes into
16 - 21 ÷ 7 + 6 x 3 = 16 - 3 + 18 = 31

1. 5 x 15 ÷ 7 - 20 + 4 = 77

1. Lets try all options one by one.

##### Correct Option: C

If we interchanges signs '+' and '÷', then the equation changes into
5 x 15 + 7 - 20 ÷ 4 = 5 x 15 + 7 - 5 = 77

1. 4 x 2 + 6 ÷ 2 - 12 = 2

1. Lets try all options one by one.

##### Correct Option: A

If we interchanges signs '÷' and 'x', then the equation changes into
4 ÷ 2 + 6 x 2 - 12 = 2 + 12 - 12 - 2

1. 3 - 9 x 27 + 9 ÷ 3 = 3

1. Lets try all options one by one.

##### Correct Option: E

If we interchange 'x' and '-' , the equation changes into
3 x 9 - 27 + 9 ÷ 3 = 27 - 27 + 3 = 3

1. if 'R' means '÷', 'Q' means 'x', 'P' means '+', then 1 8 R 9 P 2 Q 8 = ?

1. Using the correct symbols, we have
1 8 R 9 P 2 Q 8
= 18 ÷ 9 + 2 x 8

##### Correct Option: A

Using the correct symbols, we have
1 8 R 9 P 2 Q 8
= 18 ÷ 9 + 2 x 8
= 2 + 2 x 8 = 2 + 16 = 18