← Back to course
Number Trail Grade 1 / Week 11 / Monday
1/6
Week 11 · Add and subtract tens

Monday

Add tens
// Bigger numbers, tens and ones
⏱ about 15 min

Monday: Add tens

Hazel the Hedgehog keeps her pencils in boxes of ten.

She has 3 boxes. Bennie the Bear brings 2 more.

"How many pencils now?" Hazel asks.

Learn it: tens plus tens

Bennie counts the boxes. 3 tens and 2 tens.

3 tens and 2 tens make 5 tens.

Five tens are 50.

So 30 plus 20 is 50.

Base-ten blocks: 5 tens

It is like 3 plus 2, but with tens!

ADD THE TENS
  • Read the question.
  • Tap your answer.
30 + 20 = ?
Base-ten blocks: 4 tens40 + 10 = ?
20 + 60 = ?
50 + 40 = ?

Use a fact you know

Hazel knows 4 plus 3 is 7.

So 4 tens and 3 tens make 7 tens.

That is 70.

SMALL FACT, BIG FACT
  • Read the question.
  • Tap your answer.
A ten-frame with four red counters and three gold counters4 + 3 = ?
40 + 30 = ?
6 + 2 = ?
60 + 20 = ?
COUNT BY TENS TO 60
  • Start with 20.
  • Add one ten each time.
11st
22nd
33rd
44th
55th
Number sentenceTrue or false?
30 + 20 = 50?
10 + 70 = 70?
20 + 20 = 40?
WHY THIS EXERCISE1 ten and 7 tens make 8 tens. That is 80.
Try it
Make 2 piles of 10 blocks.
Make 1 more pile of 10.
Count all the piles by tens.
You found 20 plus 10 is 30!
Draw 3 boxes of ten pencils and 2 more boxes.

Word Spot: them

Here are new sight words.

Look at each word. Say it. Spell it.

Them: T-H-E-M.

FIND THE WORD
  • Listen to the word.
  • Tap it.
Find the word you hear.
Find the word you hear.
FILL THE GAP
  • Listen to the sentence.
  • Tap the missing word.
Give ___ some water.
I see the birds. I like ___.

Great adding! Tomorrow we add tens to any number.