Standard way of counting in Japanese, for eg counting money. However, some objects/things are counted differently.

{漢語|かんご}

いち、に、さん、し・よん、後、ろく、しち・なな、はち、く・きゅう

  • し、く given alternative sounds because of superstition (death and agony)
  • しち given alternative sound because sounds too much like いち
    Memorize which pronunciation to use in which case! よん、なな、きゅう are the “preferred” pronunciation in most cases

{百|ひゃく}

3/6/8 has changes

  • さんびゃく
  • ろっぴゃく
  • はっぴゃく

4/7/9 uses preferred pronunciation

  • よんひゃく
  • ななひゃく
  • きゅうひゃく

{千|せん}

3/8 has changes

  • さんぜん
  • はっせん

4/7/9 uses preferred pronunciation

  • よんせん
  • ななせん
  • きゅうせん

{万|まん}、{億|おく}、{兆|ちょう}

10k, 100M, 1T

{大和言葉|やまとことば}・{和語|わご}

{一つ|ひとつ}、{二つ|ふたつ}、{三つ|みっつ}、{四つ|よっつ}、{五つ|いつつ}、{六つ|むっつ}、{七つ|ななつ}、{八つ|やっつ}、{九つ|ここのつ}、{十|とお}

Typically only used up to 10