Twelve days after Mankato students returned from winter break on Jan. 3, they got a day off for the Martin Luther King Jr. holiday.

A week later, they got another day off for teachers to work on class preparation.

Three weeks later, they had five days off for an early spring break.

Three days later, it snowed hard, so students spent two more days at home.

March 19 and 30, students will be out of school again — this time for teacher preparation/curriculum days. There will be more days off in April around Easter and in May.

Which begs the question: Just how often are kids in school?

By law, students can’t start school until after Labor Day, and they usually get out in early June.

Throw in holidays, winter and spring break, snow days and a few teacher improvement/preparation/curriculum days, and here’s what you get:

About 172.

That’s the average number of student instruction days in schools across Minnesota — meaning out of the 365 days in a year, kids are in school less than 50 percent of the time.

In Mankato last year and this year, kids in K-12 are in session for about 168 days.

At Minnesota New Country, a charter school in Henderson, kids met for 144 days last year.

Minnesota does not require school districts to host a minimum number of days — it’s the only state that doesn’t — and it’s evident in some school districts this year.

Lake Crystal Wellcome Memorial cut several days of instruction to allow time for kids and staff to transfer into a new high school. Le Sueur-Henderson will shave nearly three weeks off the tail end of the year to allow construction workers ample time to complete a high school addition.

The state believes tests, not school days, are the best gauge of student achievement, said Chas Anderson, deputy education commissioner for the Minnesota Department of Education.