SME
Grade 4 Math · Problem type
Add tenths and hundredths
Use this for “Find the value of 6/10 + 7/100” and write the sum as a decimal (sums under one whole).
Diagram
34 of 100 squares shaded
This is an example. Type your own values to start a new problem.
Tenths
10
+
Hundredths
100
=
Hundredths in all
100
=
The sum as a decimal
The tenths as hundredths
worked out (not typed)
Formulas
3
10
=
30
100
Tenths × 10 = the same amount in hundredths
30
100
+
4
100
=
34
100
The tenths as hundredths over 100 + hundredths over 100 = hundredths in all over 100
34
100
=
0.34
Hundredths in all, written as a decimal = the sum as a decimal
Assumptions
•
A tenth is 10 hundredths, so 3/10 = 30/100. Write the tenths as hundredths first.
•
Then add the hundredths. The sum is in hundredths.
•
Hundredths written as a decimal: 34/100 = 0.34. The sum stays less than one whole.
Step-by-step
WE KNOW
Tenths: 3
Hundredths: 4
FIND
the tenths as hundredths, hundredths in all, the sum as a decimal
Step 1 · Find the tenths as hundredths
3
10
=
?
100
Tenths × 10 = the same amount in hundredths
Each tenth is 10 hundredths: one column of the hundred grid.
The tenths as hundredths = 3 × 10
The tenths as hundredths = 30
Step 2 · Find hundredths in all
30
100
+
4
100
=
?
100
The tenths as hundredths over 100 + hundredths over 100 = hundredths in all over 100
Now both parts are hundredths. Add them.
Hundredths in all = 30 + 4
Hundredths in all = 34
Step 3 · Find the sum as a decimal
34
100
=
?
Hundredths in all, written as a decimal = the sum as a decimal
Hundredths go two places after the point: the last digit is in the hundredths place.
The sum as a decimal = 34 hundredths
The sum as a decimal = 0.34
Check
Put the numbers back in. Both sides should match.
3
10
=
30
100
✓
30
100
+
4
100
=
34
100
✓
34
100
=
0.34
✓
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