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

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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: earthworms tunnel through soil and let air in; they drag dead leaves underground; their waste makes the soil richer. What is its main idea?
  • A.Leaves fall in the fall.
  • B.Earthworms help keep soil healthy.
  • C.Earthworms live underground.
2.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.Phones take photos.
  • B.Walls hold phones.
  • C.Telephones have changed a great deal over time.
3.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 home to a great deal of sea life.
  • B.Fish lay eggs.
  • C.Coral reefs are very small.
4.A paragraph says: Fleming saw mold kill germs; Florey and Chain found a way to make it in large amounts; by 1944 it was treating soldiers. What is its main idea?
  • A.Making penicillin into a medicine took the work of many people.
  • B.Soldiers were wounded in 1944.
  • C.Mold grows in dishes.
5.A paragraph says: honeybees carry pollen from flower to flower; without them many fruits would not grow; farmers rent hives for their orchards. What is its main idea?
  • A.Bees are important for growing food.
  • B.Flowers have pollen.
  • C.Farmers keep hives.
6.A paragraph says: beavers fell trees with their teeth; they build dams of sticks and mud; their ponds give homes to fish and birds. What is its main idea?
  • A.Fish live in ponds.
  • B.Beavers have sharp teeth.
  • C.Beavers change the places where they live.
7.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.Trains were often late.
  • B.Towns had clocks.
  • C.The railways led to one time for the whole country.
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.Romans liked straight lines.
  • B.Roman roads were built to last.
  • C.Water drains away.

LessonPrint · RI.4.2 · Set 2 · free to copy for classroom use

Answer key — Main Idea and Its Support

Set 2. Prints on its own sheet.

  1. 1.Earthworms help keep soil healthy.
  2. 2.Telephones have changed a great deal over time.
  3. 3.Coral reefs are home to a great deal of sea life.
  4. 4.Making penicillin into a medicine took the work of many people.
  5. 5.Bees are important for growing food.
  6. 6.Beavers change the places where they live.
  7. 7.The railways led to one time for the whole country.
  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.