Skip counting means counting by the same jump each time. You already count by tens (Counting by Tens). Now count by 5s, 10s and 100s, starting from any number up to 1,000.
Por qué funciona
Adding 10 adds one more ten, so only the tens digit goes up by 1. Adding 100 adds one more hundred, so only the hundreds digit goes up. Adding 5 to a number that ends in 0 or 5 makes the ones digit flip: 0, 5, 0, 5.
Ejemplo resuelto: Count by 10s across a hundred
Count by 10s from 470.
- 470, 480, 490: only the tens digit changes.
- 10 more than 490 makes 10 tens, which is a new hundred.
- So the next numbers are 500, 510, 520.
Respuesta: 470, 480, 490, 500, 510, 520
Ejemplo resuelto: Count by 100s
Count by 100s from 160.
- Only the hundreds digit changes.
- 160, 260, 360, 460, 560.
Respuesta: 160, 260, 360, 460, 560
Ejemplo resuelto: Count by 5s
Count by 5s from 35.
- The ones digit goes 5, 0, 5, 0.
- 35, 40, 45, 50, 55, 60.
Respuesta: 35, 40, 45, 50, 55, 60
Idea clave
Skip counting adds the same amount each time. Counting by 10s changes the tens digit; counting by 100s changes the hundreds digit.
Error común
After 490, writing “4100.” The tens place can’t hold 10. When the tens reach 10, they make a new hundred: $490 + 10 = 500$.
Grown-up tip: Count nickels by 5s and dimes by 10s, or count by 100s as you climb the stairs.