A 7-year-old student of Monte Cristo Elementary School in Edinburg, Texas, penned a heart-breaking letter to Santa Claus, during a classroom exercise.

First grade teacher Ruth Espiricueta told her students to write a letter to Santa Claus asking him for something they wanted and something they needed. The exercise was devised to teach the students the difference between “need” and “want.”

While evaluating her students’ answer sheets, Espiricueta came across an answer that tugged at her heartstrings.

“I have [been] good this day. This Christmas I would like a ball and a food. I need a [blanket],” a student had written.

"I had no idea she was going through hard times being that she is always at school with a big smile," Espiricueta said of her student. "Her act of unselfishness made me realize that I needed to share this with others."

Next day, Espiricueta asked the student about her letter to Santa. The little girl said she wanted a ball instead of a doll because then both she and her brother could play with it.

When asked why she called food a “want” instead of a “need,” the student had a simple explanation. “Well, I get to eat at school – sometimes I may not have at home, but I get to eat at school,” the girl replied, Espiricueta told CBS affiliate KGBT. “A blanket I have one, but it's not warm enough."

When the girl’s mother Maria Cortez heard about her daughter plea to Santa Claus, she could not hold back her tears.

“I'm just very emotional and proud of my children, because I raise them to appreciate the little that we have," Cortez said.

The girl’s heartrending letter is not unlike many of her peers who are forced to live in poverty, her teacher said.

"Unfortunately, there are other students that, as part of their needs, they included food, towels, blankets, pillows, bed, clothes, shoes and a stove," Espiricueta told ABC News. "Some of my students were not even excited about Christmas because they know that their parents cannot afford to buy a Christmas tree or gifts for them."

According to 2016 data from the U.S. Census Bureau, more than one in five children in the state live in less than privileged conditions.

"I never expected for students to ask for things we usually take for granted," Espiricueta added. "I was heartbroken because no one should ever go hungry or be cold on winter nights."

Espiricueta said the thought of her own children going hungry or cold during the holidays was unbearable for her so she decided to post a picture of the letter on Facebook. Soon donations began to pour in from many people who came across Espiricueta’s post.

It also led the school’s principal to start a donation drive, with a goal of distributing 724 blankets this Christmas, to help all the students of the school stay warm. They are still running short of 108 blankets.