Main Idea and Key Details is a free printable Grade 3 English worksheet on matching a main idea to the key detail that supports it, aligned to Common Core standard RI.3.2. It prints 3 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 10 of 25 · the same problems every time you open this link.
Set 1 has all 25 in a single PDF. All 25 sets ask different questions.
Main Idea and Key Details
RI.3.2
NameDate
Write the letter of the detail next to each main idea.
1.Write the letter of the key detail that supports each main idea.
Bees work together to run the hive.
A windmill turns moving air into turning stone.
A salmon returns to the river where it hatched.
Volcanoes form where melted rock escapes from the Earth.
A.It finds the river by its smell.
B.Some bees collect nectar while others guard the door.
C.The sails turn a shaft that turns the millstone.
D.Lava pours out through a crack and cools into rock.
2.Write the letter of the key detail that supports each main idea.
Louis Braille invented a way for blind people to read.
Beavers change rivers by building dams.
Frogs change shape as they grow.
A canal lock lets boats climb hills.
A.He used a cell of six raised dots.
B.A tadpole grows back legs before front legs.
C.Water flows in and the boat rises with it.
D.They pile up sticks and mud until the water backs up.
3.Write the letter of the key detail that supports each main idea.
Cheese is made by separating the protein in milk.
Trees help keep soil in place.
Morse code turns letters into short and long signals.
Lighthouses keep ships away from rocks.
A.Their roots hold the earth together in heavy rain.
B.E is one dot and T is one dash.
C.Rennet splits the milk into curds and whey.
D.Their lamps flash a pattern sailors can see at night.
LessonPrint · RI.3.2 · Set 10 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 10. Prints on its own sheet.
1.1. Bees work together to run the hive. — B (Some bees collect nectar while others guard the door.) 2. A windmill turns moving air into turning stone. — C (The sails turn a shaft that turns the millstone.) 3. A salmon returns to the river where it hatched. — A (It finds the river by its smell.) 4. Volcanoes form where melted rock escapes from the Earth. — D (Lava pours out through a crack and cools into rock.)
2.1. Louis Braille invented a way for blind people to read. — A (He used a cell of six raised dots.) 2. Beavers change rivers by building dams. — D (They pile up sticks and mud until the water backs up.) 3. Frogs change shape as they grow. — B (A tadpole grows back legs before front legs.) 4. A canal lock lets boats climb hills. — C (Water flows in and the boat rises with it.)
3.1. Cheese is made by separating the protein in milk. — C (Rennet splits the milk into curds and whey.) 2. Trees help keep soil in place. — A (Their roots hold the earth together in heavy rain.) 3. Morse code turns letters into short and long signals. — B (E is one dot and T is one dash.) 4. Lighthouses keep ships away from rocks. — D (Their lamps flash a pattern sailors can see at night.)
More practice for RI.3.2
State the main idea and show which details hold it up.