Grado 3Fractions3.NF.A.3a

Equivalent Fractions

1/2 and 2/4 name the same point and the same amount.

Sin empezar Ir a la práctica

Esta lección aún no está traducida. Por ahora se muestra en inglés; la versión en español está en camino.

On the number line, $\frac{4}{4}$ and 1 named the same point. Different fractions can share a point too. They are called equivalent fractions.

$\frac{2}{4}$ lines up with $\frac{1}{2}$ and with $\frac{4}{8}$ on the lines below. Same point, three names.

Por qué funciona

Start with $\frac{1}{2}$ of a bar. Cut each half into 2 equal pieces: now the bar has 4 pieces, and the shaded part is 2 of them, $\frac{2}{4}$. You made more pieces, but each piece is half as big, so the shaded amount did not change. That is why bigger numbers in a fraction do not mean a bigger amount.
Use "Cut each part into" to cut the halves into 2, 3 or 4 pieces. The shading stays the same size: $\frac{1}{2} = \frac{2}{4} = \frac{3}{6} = \frac{4}{8}$.

Idea clave

Equivalent fractions are the same size and sit at the same point on the number line, like $\frac{1}{2} = \frac{2}{4}$ and $\frac{2}{3} = \frac{4}{6}$.

Ejemplo resuelto: Halves and fourths

$\frac{1}{2} = \frac{\square}{4}$
  1. Each half is the same as 2 fourths.
  2. So 1 half is 2 fourths.

Respuesta: $2$

Ejemplo resuelto: Thirds and sixths

$\frac{2}{3} = \frac{\square}{6}$
  1. Each third is 2 sixths.
  2. 2 thirds is $2 \times 2 = 4$ sixths.

Respuesta: $4$

Ejemplo resuelto: Going back

$\frac{6}{8} = \frac{\square}{4}$
  1. 2 eighths make 1 fourth.
  2. 6 eighths make $6 \div 2 = 3$ fourths.

Respuesta: $3$

Error común

Thinking $\frac{2}{4}$ is bigger than $\frac{1}{2}$ because its numbers are bigger. The 4 means smaller pieces. Line the bars up: the shading for $\frac{2}{4}$ ends exactly where the shading for $\frac{1}{2}$ ends.

Práctica

Apruebas con 3 respuestas correctas, las 2 últimas seguidas. Cada respuesta correcta da 2 XP.

Cargando la práctica…

Se apoya en

Lleva a

Fuentes y lecturas

  • Common Core State Standards for Mathematics, Grade 3, 3.NF.A.3a (two fractions are equivalent if they are the same size or the same point on a number line)
  • Common Core State Standards for Mathematics, Grade 3, 3.NF.A.3b (recognize and generate simple equivalent fractions)