How the word "ななじゅう（七十）" is translated into English
七十円の切手をください。
ここから駅まで七十メートルぐらいです。
おばあさんは七十歳ですか。
"ななじゅう（七十）" is in the lesson "Big numbers" (Level 4), along with 11 other useful words. LinDuo has 180 topic lessons like this one, 2,379 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.
