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 16 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 canal lock lets boats climb hills.
Volcanoes form where melted rock escapes from the Earth.
A salmon returns to the river where it hatched.
Swallows leave Britain to follow their food.
A.Lava pours out through a crack and cools into rock.
B.Water flows in and the boat rises with it.
C.Flying insects disappear in October.
D.It finds the river by its smell.
2.Write the letter of the key detail that supports each main idea.
Yeast makes bread rise.
Beavers change rivers by building dams.
Morse code turns letters into short and long signals.
Cheese is made by separating the protein in milk.
A.Rennet splits the milk into curds and whey.
B.E is one dot and T is one dash.
C.It gives off gas that is trapped in the dough.
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.
Lighthouses keep ships away from rocks.
Trees help keep soil in place.
Bees work together to run the hive.
A windmill turns moving air into turning stone.
A.Their roots hold the earth together in heavy rain.
B.The sails turn a shaft that turns the millstone.
C.Their lamps flash a pattern sailors can see at night.
D.Some bees collect nectar while others guard the door.
LessonPrint · RI.3.2 · Set 16 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 16. Prints on its own sheet.
1.1. A canal lock lets boats climb hills. — B (Water flows in and the boat rises with it.) 2. Volcanoes form where melted rock escapes from the Earth. — A (Lava pours out through a crack and cools into rock.) 3. A salmon returns to the river where it hatched. — D (It finds the river by its smell.) 4. Swallows leave Britain to follow their food. — C (Flying insects disappear in October.)
2.1. Yeast makes bread rise. — C (It gives off gas that is trapped in the dough.) 2. Beavers change rivers by building dams. — D (They pile up sticks and mud until the water backs up.) 3. Morse code turns letters into short and long signals. — B (E is one dot and T is one dash.) 4. Cheese is made by separating the protein in milk. — A (Rennet splits the milk into curds and whey.)
3.1. Lighthouses keep ships away from rocks. — C (Their lamps flash a pattern sailors can see at night.) 2. Trees help keep soil in place. — A (Their roots hold the earth together in heavy rain.) 3. Bees work together to run the hive. — D (Some bees collect nectar while others guard the door.) 4. A windmill turns moving air into turning stone. — B (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.