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 9 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.
Yeast makes bread rise.
Frogs change shape as they grow.
A canal lock lets boats climb hills.
Swallows leave Britain to follow their food.
A.A tadpole grows back legs before front legs.
B.Water flows in and the boat rises with it.
C.It gives off gas that is trapped in the dough.
D.Flying insects disappear in October.
2.Write the letter of the key detail that supports each main idea.
Morse code turns letters into short and long signals.
Volcanoes form where melted rock escapes from the Earth.
Trees help keep soil in place.
A salmon returns to the river where it hatched.
A.Their roots hold the earth together in heavy rain.
B.E is one dot and T is one dash.
C.It finds the river by its smell.
D.Lava pours out through a crack and cools into rock.
3.Write the letter of the key detail that supports each main idea.
Cheese is made by separating the protein in milk.
Beavers change rivers by building dams.
Louis Braille invented a way for blind people to read.
Lighthouses keep ships away from rocks.
A.He used a cell of six raised dots.
B.Their lamps flash a pattern sailors can see at night.
C.They pile up sticks and mud until the water backs up.
D.Rennet splits the milk into curds and whey.
LessonPrint · RI.3.2 · Set 9 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 9. Prints on its own sheet.
1.1. Yeast makes bread rise. — C (It gives off gas that is trapped in the dough.) 2. Frogs change shape as they grow. — A (A tadpole grows back legs before front legs.) 3. A canal lock lets boats climb hills. — B (Water flows in and the boat rises with it.) 4. Swallows leave Britain to follow their food. — D (Flying insects disappear in October.)
2.1. Morse code turns letters into short and long signals. — B (E is one dot and T is one dash.) 2. Volcanoes form where melted rock escapes from the Earth. — D (Lava pours out through a crack and cools into rock.) 3. Trees help keep soil in place. — A (Their roots hold the earth together in heavy rain.) 4. A salmon returns to the river where it hatched. — C (It finds the river by its smell.)
3.1. Cheese is made by separating the protein in milk. — D (Rennet splits the milk into curds and whey.) 2. Beavers change rivers by building dams. — C (They pile up sticks and mud until the water backs up.) 3. Louis Braille invented a way for blind people to read. — A (He used a cell of six raised dots.) 4. Lighthouses keep ships away from rocks. — B (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.