Umm you divide...
The best way to estimate a quotient using compatible numbers is to first understand how compatible numbers work. They are numbers that are close in value to the actual numbers and are easily added, subtracted or divided.
i think it is 28x26
300 + 60
23.3043
119.3333
70.013
94
280 + 500 = 780
77
That equals 559. If you have to, estimate 210 + 350 = 560
6.9877