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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 23 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: 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.
2.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.Stores sell bags.
  • B.Turtles eat jellyfish.
  • C.Plastic bags harm the natural world.
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: 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.Farmers keep hives.
  • B.Bees are important for growing food.
  • C.Flowers have pollen.
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.Towns had clocks.
  • B.The railways led to one time for the whole country.
  • C.Trains were often late.
6.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.
7.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.Beavers change the places where they live.
  • B.Fish live in ponds.
  • C.Beavers have sharp teeth.
8.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 live underground.
  • C.Earthworms help keep soil healthy.

LessonPrint · RI.4.2 · Set 23 · free to copy for classroom use

Answer key — Main Idea and Its Support

Set 23. Prints on its own sheet.

  1. 1.Roman roads were built to last.
  2. 2.Plastic bags harm the natural world.
  3. 3.Telephones have changed a great deal over time.
  4. 4.Bees are important for growing food.
  5. 5.The railways led to one time for the whole country.
  6. 6.Making penicillin into a medicine took the work of many people.
  7. 7.Beavers change the places where they live.
  8. 8.Earthworms help keep soil healthy.

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.