First graders discover that a two-digit number is made of groups of ten plus extra ones — so 34 is really 3 tens and 4 ones — the big idea that makes bigger numbers easy to understand.
Students will be able to…
The number 34 looks like just two digits — but it’s really 3 groups of ten and 4 extra ones. How do tens and ones build every number?
Project this and change the tens and ones. Watch the rods and cubes build the number — tens are groups of ten, ones are singles!
Tap any phase to open the teacher moves and student actions.
Counting 34 one-by-one is slow — is there a faster way?
Teacher models.
Class uses Build a Number.
Students build numbers.
One number.
Aligned to the Common Core State Standards for Mathematics.
Understand that two-digit numbers represent amounts of tens and ones.
Understand 10 can be thought of as a bundle of ten ones (a “ten”).
Mentally find 10 more or 10 less than a number.
Look for and make use of structure in place value.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have families group small objects (like beans or cereal) into piles of ten, then count the tens and leftover ones to name the number. A printable place-value mat is in the Math library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.