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 23 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.
A windmill turns moving air into turning stone.
Lighthouses keep ships away from rocks.
Volcanoes form where melted rock escapes from the Earth.
Cheese is made by separating the protein in milk.
A.Their lamps flash a pattern sailors can see at night.
B.The sails turn a shaft that turns the millstone.
C.Rennet splits the milk into curds and whey.
D.Lava pours out through a crack and cools into rock.
2.Write the letter of the key detail that supports each main idea.
Frogs change shape as they grow.
A salmon returns to the river where it hatched.
Louis Braille invented a way for blind people to read.
Bees work together to run the hive.
A.It finds the river by its smell.
B.A tadpole grows back legs before front legs.
C.He used a cell of six raised dots.
D.Some bees collect nectar while others guard the door.
3.Write the letter of the key detail that supports each main idea.
Trees help keep soil in place.
Morse code turns letters into short and long signals.
A canal lock lets boats climb hills.
Yeast makes bread rise.
A.Their roots hold the earth together in heavy rain.
B.E is one dot and T is one dash.
C.Water flows in and the boat rises with it.
D.It gives off gas that is trapped in the dough.
LessonPrint · RI.3.2 · Set 23 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 23. Prints on its own sheet.
1.1. A windmill turns moving air into turning stone. — B (The sails turn a shaft that turns the millstone.) 2. Lighthouses keep ships away from rocks. — A (Their lamps flash a pattern sailors can see at night.) 3. Volcanoes form where melted rock escapes from the Earth. — D (Lava pours out through a crack and cools into rock.) 4. Cheese is made by separating the protein in milk. — C (Rennet splits the milk into curds and whey.)
2.1. Frogs change shape as they grow. — B (A tadpole grows back legs before front legs.) 2. A salmon returns to the river where it hatched. — A (It finds the river by its smell.) 3. Louis Braille invented a way for blind people to read. — C (He used a cell of six raised dots.) 4. Bees work together to run the hive. — D (Some bees collect nectar while others guard the door.)
3.1. Trees help keep soil in place. — A (Their roots hold the earth together in heavy rain.) 2. Morse code turns letters into short and long signals. — B (E is one dot and T is one dash.) 3. A canal lock lets boats climb hills. — C (Water flows in and the boat rises with it.) 4. Yeast makes bread rise. — D (It gives off gas that is trapped in the dough.)
More practice for RI.3.2
State the main idea and show which details hold it up.