The two expressions on either side of the equal sign will have the same value if two numbers on the left-hand side are interchanged and two signs on the right-hand side are interchanged.
What are those two numbers (not digits) and the two signs?
9 × 1 ÷ 3 + 8 – 7 = 12 ÷ 3 + 2 × 33 – 13
1
3 and 8; + and -
2
1 and 9; ÷ and ×
3
3 and 7; + and ÷
4
1 and 3; + and ×