Title: Vietnamese đồng
Content:  The đồng (sign: ₫ or informally đ; code: VND) has been the currency of Vietnam since 3 May 1978. It is issued by the State Bank of Vietnam. The đồng was also the currency of the predecessor states of North Vietnam and South Vietnam, having replaced the previously used French Indochinese piastre. Formerly, it was subdivided into 10 hào, which were further subdivided into 10 xu, neither of which are now used. The Vietnamese đồng has increasingly moved towards exclusively using banknotes; as of 2012 the use of coins has decreased greatly, and since 2014 coins are generally not accepted in retail, but will still be accepted in some, but not all, banks. The Vietnamese đồng is currently the third weakest circulating currency as of May 2021 (behind Venezuelan bolivar and Iranian rial), with one United States dollar equalling 23112.04 đồng.
Title: Economy of Vietnam
Content:  Vietnam's currency is VND or đ (đồng).
Title: Vietnamese đồng
Content:  In the Vietnamese language, đồng can be used as a generic term for any currency by adding the name of a country as a qualifier. This practice is more common for more esoteric units of currency. In present-day Vietnam, when mentioning an amount of money, the currency can be (and usually is) omitted.
Title: State of Vietnam
Content:   The currency used within the French Union was the French Indochinese piastre. Notes were issued and managed by the "Issue Institute of the States of Cambodia, Laos and Vietnam" (Institut d’Emission des Etats du Cambodge, du Laos et du Viêt-Nam).
Title: Tiền
Content:   The tiền (Hán tự: 錢) was a currency used in Vietnam during the 19th and 20th centuries. The name is a cognate with the Chinese qián (錢), a unit of weight called "mace" in English. In the early 19th century, silver and gold bars were traded as currency in imperial Vietnam with values of up to 10 tiền (approximately 40 grams, or 1 tael). Bars of 1 tiền weighed between 3 and 4 grams. During this time, silver and gold coins were minted (using Vietnamese characters and design, but of types resembling either Chinese cash or Western coins) with denominations of up to 10 tiền being minted. During the Minh Mạng period (1820–1841) dragons on silver tiền coins were often depicted facing dexter (to the right), while during the Thiệu Trị period (1841–1847) and later these coins depicted dragons guardant (facing forwards). These coins continued to be minted in varying quantities into the 20th century in French Indochina, although circulating alongside the French Indochinese piastre.
Title: Vietnamese units of measurement
Content:  the basic units of Vietnamese currency were quan (貫, quán), tiền, and đồng. One quan was 10 tiền, and one tiền was between 50 and 100 đồng, depending on the time period.  Under French colonial rule, Vietnam used the units hào, xu, chinh, and cắc. After independence, Vietnam used đồng, hào, and xu, with 1 đồng equaling 10 hào or 100 xu. After the Vietnam War, chronic inflation caused both subdivisions to fall out of use, leaving đồng as the only unit of currency. However, Overseas Vietnamese communities continue to use hào and xu to refer to the tenth and hundredth denominations, respectively, of a foreign currency, such as xu for the American cent.
Title: Economy of Vietnam
Content:  The exchange rate between the U.S. dollar and the Vietnamese đồng is important because the dong, although not freely convertible, is loosely pegged to the dollar through an arrangement known as a "crawling peg". This mechanism allows the dollar–dong exchange rate to adjust gradually to changing market conditions. As of December 5, 2018, a US dollar is worth 23,256 Vietnamese đồng. Gold still maintains its position as a physical currency to a certain extent, although it has seen its economic role declining in recent years.
Title: Vietnamese đồng
Content:  In 1946, the Viet Minh government (later to become the government of North Vietnam) introduced its own currency, the đồng, to replace the French Indochinese piastre at par. Two revaluations followed, in 1951 and 1959; the first was at a rate of 100:1, the second at a rate of 1,000:1.
Title: Vietnamese cash
Content:  After the Democratic Republic of Vietnam declared their independence in 1945 they began issuing their own money, but cash coins continued to circulate in the remote areas of Bắc Bộ and Trung Bộ where there was a lack of xu, hào, and đồng coins for the population. The Democratic Republic of Viet Nam Decree 51/SL of 6 January 1947 officially set the exchange rate at twenty Vietnamese cash coins for one North Vietnamese đồng making them equal to five xu each. Vietnamese cash coins continued to officially circulate in the Democratic Republic of Vietnam until 13 April 1948.
Title: Vietnamese cash
Content:  Vietnamese cash ( văn tiền; chữ Nôm: đồng tiền; sapèque) is a cast round coin with a square hole that was an official currency of Vietnam from the Đinh dynasty in 970 until the Nguyễn dynasty in 1945, and remained in circulation in North Vietnam until 1948. The same type of currency circulated in China, Japan, Korea, and Ryūkyū for centuries. Though the majority of Vietnamese cash coins throughout history were copper coins, lead, iron (from 1528) and zinc (from 1740) coins also circulated alongside them often at fluctuating rates (with 1 copper cash being worth 10 zinc cash in 1882). Coins made from metals of lower intrinsic value were introduced because of various superstitions involving Vietnamese people burying cash coins, as the problem of people burying cash coins became too much for the government. Almost all coins issued by government mints tended to be buried mere months after they had entered circulation. The Vietnamese government began issuing coins made from an alloy of zinc, lead, and tin. As these cash coins tended to be very fragile, they would decompose faster if buried, which caused the Vietnamese people to stop burying their coins.

Question: what currency should you take to vietnam?
Answer: Vietnamese dong.