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Number Trail Grade 5 / Week 04 / Monday
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Week 04 · Divide by two-digit numbers

Monday

Divide with tens
// Estimate, divide in chunks and check
⏱ about 15 min

Monday: Divide with tens

Samantha the Squirrel bounds down the oak tree with her cheeks full of acorns.

"I have 240 acorns!" she says. "I want to hide them in 30 equal piles."

Bennie the Bear sits down beside her. "How many acorns go in each pile?"

Samantha bounces from paw to paw. "Fun fact: I know 24 ÷ 3 = 8!"

"That fact helps," says Bennie. "240 is 24 tens, and 30 is 3 tens."

"So 24 tens ÷ 3 tens is also 8."

Samantha does a happy spin. "Eight acorns in each pile!"

Learn it: use a basic fact

24 ÷ 3 = 8.

240 ÷ 30 = 8, because 30 × 8 = 240.

2,400 ÷ 30 = 80, because 30 × 80 = 2,400.

Count the zeros, and check each answer by multiplying.

Three groups of eight dots

Learn it: estimate with friendly numbers

To estimate 2,592 ÷ 36, change the numbers to ones that divide easily.

36 is close to 40. A number near 2,592 that 40 divides easily is 2,800.

2,800 ÷ 40 = 70, so the quotient is about 70.

USE A BASIC FACT
  • Read the question.
  • Tap your answer.
240 ÷ 30 = ?
2,400 ÷ 30 = ?
420 ÷ 70 = ?
4,500 ÷ 50 = ?
FIND THE MISSING FACTOR
  • Read the question.
  • Tap your answer.
? × 30 = 240
? × 60 = 4,200
40 × ? = 3,600
20 × ? = 1,800
ESTIMATE THE QUOTIENT
  • Read the question.
  • Tap your answer.
Estimate 2,592 ÷ 36 with 2,800 ÷ 40.
Estimate 1,213 ÷ 41 with 1,200 ÷ 40.
Estimate 478 ÷ 59 with 480 ÷ 60.
Which numbers are friendly for 3,476 ÷ 52?
SentenceTrue or false?
240 ÷ 30 = 8?
2,400 ÷ 30 = 8?
3,600 ÷ 90 = 40?
560 ÷ 80 = 7?
WHY THIS EXERCISE30 × 8 is 240, not 2,400. So 2,400 ÷ 30 = 80.
Try it
Count out 60 small things, like dry beans or paper clips.
Share them into 20 equal piles.
How many are in each pile? Write the division sentence.
Now think: what basic fact did you use?
Draw 30 equal piles of acorns that make 240 in all. Label one pile.

Bouncy work! Tomorrow we divide in friendly chunks.