Ingrid dug a trench eighteen twentieths of a meter long. The next day she dug nine twentieths of a meter more of the trench. What is a reasonable estimate of the total length of the trench?

1.00 meter.

Step-by-step explanation:

For the first day, she dug eighteen twentieth of a meter = x 1 meter

                                                                        = meters

The second day, she dug nine twentieth of a mater = x 1 meter

                                                                        = meters

Total length of the trench = +

                                          =

                                          =

                                          = 1

                                          = 1.35 meters

Total length of the trench is 1.35 meters.

A reasonable estimate of the total length of the trench is 1.00 meter.