Long and short scales
The long and short scales are two of several large-number naming systems for integer powers of ten, that use the same words with different meanings:
For integers less than a thousand million (< 109) the two scales are identical. From a thousand million up (≥ 109) the two scales diverge, using the same words for different numbers; this can cause misunderstanding.
Countries where the long scale is currently used include most countries in continental Europe and most French-speaking, Spanish-speaking, and Portuguese-speaking countries except Brazil. The short scale is now used in most English-speaking and Arabic-speaking countries, in Brazil, and several other countries. Number names are rendered in the language of the country, but are similar everywhere due to shared etymology (e.g., billion is billón in Spanish). Some languages, particularly in East Asia and South Asia, have large number naming systems that are different from both the long and short scales, for example the Indian numbering system.