Good morning, class! Today’s lesson from Lindbergh Schools teachers involves math.

Consider this equation: Respect = $.

That’s the message Lindbergh teachers are sending. They claim they are being disrespected over their pay — yet teachers, on average, have received raises totaling 9.75 percent over the past three years.

That’s simply not enough, as teachers contend their salaries are lagging compared to surrounding districts and the lack of competitiveness will result in Lindbergh teachers leaving for districts that pay educators more.

That’s a legitimate concern, but we believe teachers have failed to recognize — or simply are ignoring — the efforts of the board and administration to fund salaries while grappling with the aggressive enrollment growth overwhelming the district.

As a result, teachers have been damaging Lindbergh’s stellar reputation with their protests over their pay since last summer. They’re embarking on the same path that Mehlville teachers took more than 20 years ago, when they donned black shirts sporting the asinine slogan: Budget Teachers First.

Lindbergh National Education Association President Kim Scronce told the board last summer that “a culture of fear” exists in Lindbergh.

Given the demands the LNEA made at last week’s board meeting, that simply is not true, not to mention the mean-spiritedness directed by teachers and their supporters toward anyone who dares question them.

Teachers say the issue is not solely money, but if that is truly the case, why did they sign a three-year agreement with the board that leaves salaries as the only outstanding issue?

We believe teachers are seriously deluding themselves if they believe the community will support a tax-rate hike for their pay — especially on top of 2010’s 65-cent tax-rate increase and 2014’s $34 million bond issue.

The damage teachers are doing to Lindbergh Schools was further enhanced last week by Scronce’s announcement that Lindbergh teachers will work to their contracts.

By deciding to work to contract, Lindbergh teachers are disrespecting the very community and children they’re supposed to serve. They’re sending the same greedy message that Mehlville teachers communicated more than 20 years ago.

Lindbergh teachers should heed what happened in Mehlville, as it’s taken that district nearly two decades to recover from the damage wrought by its 1990s-era teachers.