Editing Addition (section)

==== Carry ====
{{main|Carry (arithmetic)}}
[[File:Addition with carry.png|thumb|upright=1|An addition with [[Carry (mathematics)|carry]]]]
The standard algorithm for adding multidigit numbers is to align the addends vertically and add the columns, starting from the ones column on the right. If a column exceeds nine, the extra digit is "[[carry (arithmetic)|carried]]" into the next column. For example, in the following image, the ones in the addition of {{nowrap|59 + 27}} is 9 + 7 = 16, and the digit 1 is the carry.<ref group=lower-alpha>Some authors think that "carry" may be inappropriate for education; {{harvtxt|van de Walle|2004}}, p. 211 calls it "obsolete and conceptually misleading", preferring the word "trade". However, "carry" remains the standard term.</ref> An alternate strategy starts adding from the most significant digit on the left; this route makes carrying a little clumsier, but it is faster at getting a rough estimate of the sum. There are many alternative methods.