As far as its list of repair and maintenance projects goes, the state Department of Education’s school playgrounds are a drop in the bucket — about 70 out of nearly 5,000 projects that carry an estimated cost of $1.5 billion. With all the talk about overcrowding, leaky roofs and classrooms that need air conditioning, school playgrounds can be an afterthought.

But they shouldn’t be. For one, modern playground equipment must meet current quality and safety standards, which are designed to handle the high energy and questionable judgment of rambunctious children suddenly freed from the confines of the classroom. Among other things, playgrounds need appropriate cushioning surfaces and sturdy guardrails properly spaced so children can’t get trapped between them.

Just as important, the school playground can be viewed as a classroom in itself — a place where children learn important lessons that help them grow. Researchers have found that unstructured play helps keiki develop strong social skills. They learn how to communicate with one another and work through problems that might cause anxiety and stress, with little adult oversight.

They also can build physical strength and agility by climbing on structures specifically designed for that purpose — and that aren’t rusty, have exposed bolts or are burning hot from the sun.

So it was encouraging to hear the state Department of Education announce this week that it had contracted with Hawaii 3R’s to fix, replace or build anew about 100 playgrounds. The deal will cost $18 million, but the state and Hawaii 3R’s consider it a good deal.

For one, the private nonprofit says that by using only volunteers and two contracted project managers, it can work more quickly and efficiently than state workers on these smaller projects. Furthermore, Hawaii 3R’s saves the state money — more than $40 million in maintenance and repair costs, it says — and, outside donations supplement taxpayer funds.

Cost control is important in Hawaii, where outdoor structures exposed to the tropical heat, rain and salty air tend to corrode faster than elsewhere, so must be upgraded more frequently. The DOE oversees 545 playgrounds, and keeping them all in good shape will require continued investment.

School playgrounds are worth it. They contribute to the physical health and mental well-being of children. They also provide that most cherished experience for a child at school: a little fun.