>>723 ネタ回答: WolframAlpha API / node
// index.js
const {get} = require('http');
const appid = '<<YOUR WolframAlpha APP ID>>';
process.stdin.on('data', data => {
get(`http://api.wolframalpha.com/v2/query?appid=${appid}&input=${encodeURIComponent(data.toString().trim())}&podstate=Result__Step-by-step+solution&format=image&output=json`, res => {
res.setEncoding('utf8');
let body = '';
res.on('data', chunk => {body += chunk;});
res.on('end', () => {
get(JSON.parse(body).queryresult.pods.filter(({title}) => title === 'Results')[0].subpods.filter(({title}) => title === 'Possible intermediate steps')[0].img.src, res => {
res.on('data', data => {process.stdout.write(data)});
});
});
});
});
$ echo 29+15 | node . > ./test1.gif
https://i.imgur.com/QxolfNz.gif
$ echo 29+5 | node . > ./test2.gif
https://i.imgur.com/D0r3sSg.gif
$ echo 29*15 | node . > ./test3.gif
https://i.imgur.com/imvQO5g.gif

試しに一桁×一桁やってみたらなんだか微妙な計算過程に…
$ echo 5*5 | node . > ./test.gif
https://i.imgur.com/8z3kZPf.gif

あと割り算はAPIからでは計算過程のURL取れなかった