Estimate the answer to 26.6 x 24.4/ 5.67 x 4.02.

For this question, we must use BIDMAS

Brackets
Indices
Division
Multiplication
Addition
Subtraction

26.6  x  24.4  /  5.67  x 4.02

First, round all the values to their first significant figure

30 x 20 / 6 x 4

The first occurring operation in BIDMAS is Division
20/6 = 3 1/3

Now do the multiplication

30 x 3 1/3 x 4 = 400

Or you can round to the nearest whole number (although it can be more difficult if doing sums in your head)

27 x 24 / 6 x 4
27 x 4 x 4
27 x 16 = 432

The more accurately you round, the closer the estimation is to the actual answer (≈460)

1 Sig Fig = 400
Whole number = 432

78 horses

120 x .65 = 78 horses in all

120 - 78 = 42 more ducks than horses