By interchanging which two signs and two numbers (not digits) the equation will be correct?
8 – 4 × 9 + 6 ÷ 3 = 29

Correct option is B

Given: 8 – 4 × 9 + 6 ÷ 3 = 29
Option (a): + and ×, 4 and 6
The equation becomes:
8 – 6 × 9 + 4 ÷ 3
8 – 6 × 9 + 1.33
8 – 54 + 1.33
9.33 – 54
44.67 ≠ 29
Option (b): - and ×, 6 and 9
The equation becomes:
8 × 4 – 6 + 9 ÷ 3
8 × 4 – 6 + 3
32 - 6 + 3
35 - 6
29 = 29
This equals 29, so this option is correct!
Option (c): × and ÷, 8 and 4
The equation becomes:
4 – 8 ÷ 9 + 6 × 3
4 – .88 + 6 × 3
4 – .88 + 18
22 - .88
21.12 ≠ 29
Option (d): - and ×, 9 and 3
The equation becomes:
8 × 4 – 3 + 6 ÷ 9
8 × 4 – 3 + .66
32 – 3 + .66
32.66 – 3
29.66
The correct answer is option (b).