77770:110+x=708

Interpret colon as division: (77770 ÷ 110) + x = 708

• 77770 ÷ 110 = 707
• So 707 + x = 708
• x = 708 − 707 = 1

Answer: x = 1. If you want a quick check: 707 + 1 = 708, which is correct.