Tenths and Hundredths Together
Aligned to 4.NF.C.5 — Common Core State Standards for Mathematics.
What this lesson teaches
One tenth is the same as ten hundredths. To add a fraction in tenths to a fraction in hundredths, first rename the tenths as hundredths, then add because they now match.
Worked examples
Example 1
3/10 + 25/100. First rename 3/10 as hundredths: multiply top and bottom by 10 to get 30/100. Now both are hundredths: 30/100 + 25/100 = 55/100.
Example 2
6/10 + 12/100. Rename 6/10 as 60/100, then add: 60/100 + 12/100 = 72/100.
Example 3
This is exactly what the decimal point does: 0.6 + 0.12 = 0.72, because 0.6 is really 0.60.
Practice questions
- Rename 6/10 as hundredths.
- Add: 4/10 + 37/100.
- Add: 7/10 + 9/100 and write the total in hundredths.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Décimos y centésimos juntos
Un décimo es igual a diez centésimos. Para sumar una fracción en décimos con una fracción en centésimos, primero cambia los décimos a centésimos y luego suma, porque ahora coinciden.
Ejemplo 1: 3/10 + 25/100. Primero cambia 3/10 a centésimos: multiplica arriba y abajo por 10 para obtener 30/100. Ahora ambas son centésimos: 30/100 + 25/100 = 55/100.
Ejemplo 2: 6/10 + 12/100. Cambia 6/10 a 60/100 y luego suma: 60/100 + 12/100 = 72/100.
Ejemplo 3: Esto es justo lo que hace el punto decimal: 0.6 + 0.12 = 0.72, porque 0.6 en realidad es 0.60.
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