Skip to content
LessonPrint

Main Idea and Its Support is a free printable Grade 4 English worksheet on working out a main idea from the details that support it, aligned to Common Core standard RI.4.2. It prints 8 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two students in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 11 of 25 · the same problems every time you open this link.

Next setLesson plan

One paper per student

12345678910111213141516171819202122232425

Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

Main Idea and Its Support

RI.4.2

NameDate

Circle the right answer.

1.A paragraph says: coral reefs cover a tiny part of the sea floor; a quarter of all sea creatures live on them; many fish lay their eggs there. What is its main idea?
  • A.Coral reefs are very small.
  • B.Coral reefs are home to a great deal of sea life.
  • C.Fish lay eggs.
2.A paragraph says: lighthouses warn ships away from rocks; each one flashes its own pattern; sailors use the pattern to tell where they are. What is its main idea?
  • A.Lighthouses keep ships safe and help them find their way.
  • B.Rocks are dangerous.
  • C.Lights can flash.
3.A paragraph says: early phones were fixed to the wall; later phones had no cord; today's phones fit in a pocket and take photos. What is its main idea?
  • A.Telephones have changed a great deal over time.
  • B.Walls hold phones.
  • C.Phones take photos.
4.A paragraph says: plastic bags take hundreds of years to break down; turtles mistake them for jellyfish; many towns now charge for bags. What is its main idea?
  • A.Turtles eat jellyfish.
  • B.Plastic bags harm the natural world.
  • C.Stores sell bags.
5.A paragraph says: trains ran to schedules across the country; each town had kept its own time; the railways needed one time everywhere. What is its main idea?
  • A.The railways led to one time for the whole country.
  • B.Towns had clocks.
  • C.Trains were often late.
6.A paragraph says: some volcanoes pour out rivers of lava; others explode in clouds of ash; some have been quiet for thousands of years. What is its main idea?
  • A.Lava is hot.
  • B.Volcanoes behave in different ways.
  • C.Ash is gray.
7.A paragraph says: libraries lend books for free; many offer computers anyone can use; they run reading clubs for children. What is its main idea?
  • A.Computers are useful.
  • B.Children like clubs.
  • C.Libraries offer many free services to a town.
8.A paragraph says: Roman roads ran straight for miles; they were laid in layers so water drained away; some are still used today. What is its main idea?
  • A.Roman roads were built to last.
  • B.Romans liked straight lines.
  • C.Water drains away.

LessonPrint · RI.4.2 · Set 11 · free to copy for classroom use

Answer key — Main Idea and Its Support

Set 11. Prints on its own sheet.

  1. 1.Coral reefs are home to a great deal of sea life.
  2. 2.Lighthouses keep ships safe and help them find their way.
  3. 3.Telephones have changed a great deal over time.
  4. 4.Plastic bags harm the natural world.
  5. 5.The railways led to one time for the whole country.
  6. 6.Volcanoes behave in different ways.
  7. 7.Libraries offer many free services to a town.
  8. 8.Roman roads were built to last.

More practice for RI.4.2

State the main idea, show the details behind it, and summarize.

Teaching this next? The Main Idea and a Summary is the 40-minute plan for it, with the misconceptions to expect.

All Grade 4 worksheets

Last reviewed 2026-09-05. Aligned to RI.4.2 of the Common Core State Standards for English Language Arts.