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 6 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.
Lighthouses keep ships away from rocks.
Trees help keep soil in place.
Volcanoes form where melted rock escapes from the Earth.
Louis Braille invented a way for blind people to read.
A.Lava pours out through a crack and cools into rock.
B.Their roots hold the earth together in heavy rain.
C.He used a cell of six raised dots.
D.Their lamps flash a pattern sailors can see at night.
2.Write the letter of the key detail that supports each main idea.
Morse code turns letters into short and long signals.
A salmon returns to the river where it hatched.
A windmill turns moving air into turning stone.
Bees work together to run the hive.
A.Some bees collect nectar while others guard the door.
B.E is one dot and T is one dash.
C.It finds the river by its smell.
D.The sails turn a shaft that turns the millstone.
3.Write the letter of the key detail that supports each main idea.
Frogs change shape as they grow.
Swallows leave Britain to follow their food.
Cheese is made by separating the protein in milk.
A canal lock lets boats climb hills.
A.Flying insects disappear in October.
B.A tadpole grows back legs before front legs.
C.Water flows in and the boat rises with it.
D.Rennet splits the milk into curds and whey.
LessonPrint · RI.3.2 · Set 6 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 6. Prints on its own sheet.
1.1. Lighthouses keep ships away from rocks. — D (Their lamps flash a pattern sailors can see at night.) 2. Trees help keep soil in place. — B (Their roots hold the earth together in heavy rain.) 3. Volcanoes form where melted rock escapes from the Earth. — A (Lava pours out through a crack and cools into rock.) 4. Louis Braille invented a way for blind people to read. — C (He used a cell of six raised dots.)
2.1. Morse code turns letters into short and long signals. — B (E is one dot and T is one dash.) 2. A salmon returns to the river where it hatched. — C (It finds the river by its smell.) 3. A windmill turns moving air into turning stone. — D (The sails turn a shaft that turns the millstone.) 4. Bees work together to run the hive. — A (Some bees collect nectar while others guard the door.)
3.1. Frogs change shape as they grow. — B (A tadpole grows back legs before front legs.) 2. Swallows leave Britain to follow their food. — A (Flying insects disappear in October.) 3. Cheese is made by separating the protein in milk. — D (Rennet splits the milk into curds and whey.) 4. A canal lock lets boats climb hills. — C (Water flows in and the boat rises with it.)
More practice for RI.3.2
State the main idea and show which details hold it up.