Roots of Reason
Roots of Reason
rootsofreason.org
every place has a value
Reference Chart · Grades 1-2 · 1.NBT.B.2 | 2.NBT.A.1

Place Value: Ones to Hundreds

Where a digit sits decides what it is worth.
Hundreds
Tens
Ones
3
5
4
3 hundreds = 300
5 tens = 50
4 ones = 4
300 + 50 + 4 = 354
Same digit, different place, different value: a 3 in the hundreds place is worth 300, and one place to the right it would be worth 30.
Your turn: write three numbers, then say the value of each digit
Hundreds
Tens
Ones
Roots of Reason Place tells value: read it, say it, build it. rootsofreason.org
Roots of Reason
Roots of Reason
rootsofreason.org
every place has a value
Reference Chart · Grades 3-4 · 4.NBT.A.1 | 4.NBT.A.2

Place Value: To the Hundred Thousands

Digits are read in groups of three, called periods. Read each group, then say its period name.
THOUSANDS PERIOD
ONES PERIOD
Hundred
Thousands
Ten
Thousands
Thousands
Hundreds
Tens
Ones
4
5
8,
6
0
4
400,000
50,000
8,000
600
0
4
400,000 + 50,000 + 8,000 + 600 + 4 = 458,604
Read it: "four hundred fifty-eight thousand, six hundred four." The 0 adds nothing, but it holds the tens place.
Your turn: write three numbers, with a comma after the thousands period
H-Th
T-Th
Th
H
T
O
Roots of Reason Place tells value: read it, say it, build it. rootsofreason.org
Roots of Reason
Roots of Reason
rootsofreason.org
every place has a value
Reference Chart · Grade 5 · 5.NBT.A.1 | 5.NBT.A.3

Place Value: Decimals

The pattern continues past the point. Every place is ten times the one to its right.
← ×10 each place ÷10 each place →
WHOLE NUMBERS
·
DECIMAL PLACES
Thousands
Hundreds
Tens
Ones
Tenths
1/10
Hundredths
1/100
Thousandths
1/1000
2,
4
8
3
.
1
5
6
2,000
400
80
3
0.1
0.05
0.006
2,000 + 400 + 80 + 3 + 0.1 + 0.05 + 0.006 = 2,483.156
Read the point as "and": "two thousand four hundred eighty-three and one hundred fifty-six thousandths."
Your turn: the point is already placed
.
.
.