Which of the numbers (not digits) should be interchanged in the given equation to make it mathematically correct?

$$4 + 6 \times 3 − 5 \div 2 = 16$$

Solution

$$4\ +\ 12=16$$$$4\ +\ 6\times\ 3\ -\ 5\ \frac{\ 2}{ }=16$$

5 and 6

$$4\ +\ 5\times\ 3\ -\ 6\ \frac{\ 2}{ }=16$$

$$4\ +\ 15-\ 6\ \frac{\ 2}{ }=16$$

$$4\ +\ 15-3=16$$

$$16=16$$

4 and 6

$$6\ +\ 4\times\ 3\ -\ 5\ \frac{\ 2}{ }=16$$
$$10\times\ 3\ -\ 5\ \frac{\ 2}{ }=16$$
$$30\ -\ 5\ \frac{\ 2}{ }=16$$
$$25\frac{\ 2}{ }=16$$
$$12.5=16$$

2 and 3
$$4\ +\ 6\times\ 2\ -\ 5\ \frac{\ 3}{ }=16$$
$$10\times\ 2\ -\ 5\ \frac{\ 3}{ }=16$$
$$20-\ 5\ \frac{\ 3}{ }=16$$
$$15\ \frac{\ 3}{ }=16$$
$$5=16$$

5 and 3
$$4\ +\ 6\times\ 5\ -\ 3\ \frac{\ 2}{ }=16$$
$$10\times\ 5\ -\ 3\ \frac{\ 2}{ }=16$$
$$50\ -\ 3\ \frac{\ 2}{ }=16$$
$$47\ \frac{\ 2}{ }=16$$
$$23.5=16$$
Hence option A is correct answer L.H.S=R.H.S