之前我一個大學同學教她姪兒,其中一項作業是用英文學數學。
我大學同學問我counting by 2's是什麼意思。
我上網查是說兩個一數。
但當我告訴她之後,她說她姪兒幼兒園老師竟然跟他們說,如果開始算得數字是5, "Counting by 2's",就是5、10、15等。
我看了大驚,不對吧!? 於是找英國朋友求證。
果然我大學同學姪兒的幼兒園老師誤人子弟。
我英國朋友這樣跟我說: "I would say 'counting in 2s', not 'by'.
A quick Google suggests the latter may be American (plenty of pages about "math" (sic)).
The sequence, '5, 10, 15...' is clearly counting in/by 5s, not 2s.
Starting with 5, if you count in 2s, it would give you '5, 7, 9, 11...',