Grand Rapids Addition

In the Grand Rapids, Michigan region, the streets running east–west south of downtown in the county are numbered, eight to a mile offset by four, and they run along the section lines for the current and former townships in the area. Along US 131, 76th Street falls on one of the section lines and happens to be exit 75, giving us this sign, the first to be posted for the State of Michigan with the simple addition problem of:

$$1 + 75 = 76$$