Roots of Reason
Roots of Reason
rootsofreason.org
every digit has an address
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; one place to the right it would be worth only 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 digit has an address
Reference Chart · Grades 3-4 · 4.NBT.A.1 | 4.NBT.A.2

Place Value: To the Hundred Thousands

Digits travel in groups of three - say the period, then its 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 writes nothing when you add - but it still holds the tens place.
Your turn - write three numbers, 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 digit has an address
Reference Chart · Grade 5 · 5.NBT.A.1 | 5.NBT.A.3

Place Value: Decimals

The pattern doesn't stop at 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
.
.
.