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Number Trail Grade 5 / Week 03 / Number Hunt
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Week 03 · Multiply big numbers

Number Hunt

Number Hunt
// Partial products and the standard algorithm
⏱ about 15 min

Saturday: Number Hunt

Lucy the Ladybug rides on Bennie the Bear's shoulder through the trail cabin.

"Let us hunt for things that come in equal groups," says Bennie.

Lucy points at a carton. "Twelve eggs in one carton!"

Bennie finds a box of crayons. "Twenty-four crayons in one box."

"If we had 15 boxes, how many crayons would that be?" asks Lucy.

Bennie smiles. "Let us multiply and find out together."

Lucy feels happy and brave as they search for more groups.

Hunt for equal groups

Look around your home with a grown-up.

Find things that come in equal groups, like eggs, crayons or socks.

Use big numbers of groups to make multiplying problems.

Try it: Number Hunt
Find three things that come in packs or rows.
Write how many are in one pack.
Choose a two-digit number of packs, like 15 or 32.
Multiply to find the total. Estimate first.
WHAT DID YOU LEARN?
  • Read the question.
  • Tap your answer.
A box holds 24 crayons. How many crayons are in 15 boxes?
A carton holds 12 eggs. How many eggs are in 32 cartons?
Round 24 and 15 to the nearest ten. Then multiply.
◇ CARD MULTIPLY
Write the digits 1 to 9 on nine small cards.
Each of you picks three cards and makes a three-digit number.
Pick two more cards to make a two-digit number.
Multiply your two numbers. Estimate first, then check each other.
Talk about how you felt solving a big problem.
Draw the equal groups you found and write a multiplication sentence.
For a grown-up
This week your child multiplied numbers up to four digits by two digits.
They used area models, partial products and the standard algorithm.
Ask them to explain why the second row ends in a zero.
Praise careful checking with an estimate more than a quick answer.

Great hunting! Next week Samantha helps us divide big numbers.

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