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 13 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 salmon returns to the river where it hatched.
Cheese is made by separating the protein in milk.
Volcanoes form where melted rock escapes from the Earth.
Trees help keep soil in place.
A.It finds the river by its smell.
B.Their roots hold the earth together in heavy rain.
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.
Louis Braille invented a way for blind people to read.
Swallows leave Britain to follow their food.
Morse code turns letters into short and long signals.
Frogs change shape as they grow.
A.A tadpole grows back legs before front legs.
B.E is one dot and T is one dash.
C.Flying insects disappear in October.
D.He used a cell of six raised dots.
3.Write the letter of the key detail that supports each main idea.
Yeast makes bread rise.
Lighthouses keep ships away from rocks.
A canal lock lets boats climb hills.
A windmill turns moving air into turning stone.
A.The sails turn a shaft that turns the millstone.
B.Water flows in and the boat rises with it.
C.It gives off gas that is trapped in the dough.
D.Their lamps flash a pattern sailors can see at night.
LessonPrint · RI.3.2 · Set 13 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 13. Prints on its own sheet.
1.1. A salmon returns to the river where it hatched. — A (It finds the river by its smell.) 2. Cheese is made by separating the protein in milk. — C (Rennet splits the milk into curds and whey.) 3. Volcanoes form where melted rock escapes from the Earth. — D (Lava pours out through a crack and cools into rock.) 4. Trees help keep soil in place. — B (Their roots hold the earth together in heavy rain.)
2.1. Louis Braille invented a way for blind people to read. — D (He used a cell of six raised dots.) 2. Swallows leave Britain to follow their food. — C (Flying insects disappear in October.) 3. Morse code turns letters into short and long signals. — B (E is one dot and T is one dash.) 4. Frogs change shape as they grow. — A (A tadpole grows back legs before front legs.)
3.1. Yeast makes bread rise. — C (It gives off gas that is trapped in the dough.) 2. Lighthouses keep ships away from rocks. — D (Their lamps flash a pattern sailors can see at night.) 3. A canal lock lets boats climb hills. — B (Water flows in and the boat rises with it.) 4. A windmill turns moving air into turning stone. — A (The sails turn a shaft that turns the millstone.)
More practice for RI.3.2
State the main idea and show which details hold it up.