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 25 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.
Louis Braille invented a way for blind people to read.
Swallows leave Britain to follow their food.
A windmill turns moving air into turning stone.
Yeast makes bread rise.
A.Flying insects disappear in October.
B.It gives off gas that is trapped in the dough.
C.He used a cell of six raised dots.
D.The sails turn a shaft that turns the millstone.
2.Write the letter of the key detail that supports each main idea.
Beavers change rivers by building dams.
Volcanoes form where melted rock escapes from the Earth.
Morse code turns letters into short and long signals.
Lighthouses keep ships away from rocks.
A.Lava pours out through a crack and cools into rock.
B.Their lamps flash a pattern sailors can see at night.
C.E is one dot and T is one dash.
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.
Bees work together to run the hive.
Frogs change shape as they grow.
Cheese is made by separating the protein in milk.
A salmon returns to the river where it hatched.
A.Some bees collect nectar while others guard the door.
B.A tadpole grows back legs before front legs.
C.It finds the river by its smell.
D.Rennet splits the milk into curds and whey.
LessonPrint · RI.3.2 · Set 25 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 25. Prints on its own sheet.
1.1. Louis Braille invented a way for blind people to read. — C (He used a cell of six raised dots.) 2. Swallows leave Britain to follow their food. — A (Flying insects disappear in October.) 3. A windmill turns moving air into turning stone. — D (The sails turn a shaft that turns the millstone.) 4. Yeast makes bread rise. — B (It gives off gas that is trapped in the dough.)
2.1. Beavers change rivers by building dams. — D (They pile up sticks and mud until the water backs up.) 2. Volcanoes form where melted rock escapes from the Earth. — A (Lava pours out through a crack and cools into rock.) 3. Morse code turns letters into short and long signals. — C (E is one dot and T is one dash.) 4. Lighthouses keep ships away from rocks. — B (Their lamps flash a pattern sailors can see at night.)
3.1. Bees work together to run the hive. — A (Some bees collect nectar while others guard the door.) 2. Frogs change shape as they grow. — B (A tadpole grows back legs before front legs.) 3. Cheese is made by separating the protein in milk. — D (Rennet splits the milk into curds and whey.) 4. A salmon returns to the river where it hatched. — C (It finds the river by its smell.)
More practice for RI.3.2
State the main idea and show which details hold it up.