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 24 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.
Yeast makes bread rise.
Frogs change shape as they grow.
Trees help keep soil in place.
A.It gives off gas that is trapped in the dough.
B.A tadpole grows back legs before front legs.
C.The sails turn a shaft that turns the millstone.
D.Their roots hold the earth together in heavy rain.
2.Write the letter of the key detail that supports each main idea.
Cheese is made by separating the protein in milk.
A canal lock lets boats climb hills.
Swallows leave Britain to follow their food.
Louis Braille invented a way for blind people to read.
A.Water flows in and the boat rises with it.
B.Rennet splits the milk into curds and whey.
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.
Bees work together to run the hive.
Morse code turns letters into short and long signals.
Volcanoes form where melted rock escapes from the Earth.
Beavers change rivers by building dams.
A.Some bees collect nectar while others guard the door.
B.E is one dot and T is one dash.
C.Lava pours out through a crack and cools into rock.
D.They pile up sticks and mud until the water backs up.
LessonPrint · RI.3.2 · Set 24 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 24. Prints on its own sheet.
1.1. A windmill turns moving air into turning stone. — C (The sails turn a shaft that turns the millstone.) 2. Yeast makes bread rise. — A (It gives off gas that is trapped in the dough.) 3. Frogs change shape as they grow. — B (A tadpole grows back legs before front legs.) 4. Trees help keep soil in place. — D (Their roots hold the earth together in heavy rain.)
2.1. Cheese is made by separating the protein in milk. — B (Rennet splits the milk into curds and whey.) 2. A canal lock lets boats climb hills. — A (Water flows in and the boat rises with it.) 3. Swallows leave Britain to follow their food. — C (Flying insects disappear in October.) 4. Louis Braille invented a way for blind people to read. — D (He used a cell of six raised dots.)
3.1. Bees work together to run the hive. — A (Some bees collect nectar while others guard the door.) 2. Morse code turns letters into short and long signals. — B (E is one dot and T is one dash.) 3. Volcanoes form where melted rock escapes from the Earth. — C (Lava pours out through a crack and cools into rock.) 4. Beavers change rivers by building dams. — D (They pile up sticks and mud until the water backs up.)
More practice for RI.3.2
State the main idea and show which details hold it up.