她高我五厘米 / 跟……相比: comparing without 比
【五43】比较句 / comparison
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
A + adjective + B + exact gap compares without 比 and gives the measured difference: 她高我五厘米 ("she is five centimetres taller than me"). No 比: B follows the adjective directly, and the figure comes last. It is the short, very common spoken form of the 比 sentence you already know (她比我高五厘米), with the same meaning.
It only works with adjectives you can measure: 大、小、高、重、长、早、晚 (姐姐大我三岁，她早我两天到成都). For a quality you don't put a number on (好吃、漂亮), keep the 比 sentence.
跟……相比 ("compared with") is a different tool: not a 比 sentence but an opening frame. Set B first, then comment on A freely, with 更、没有……那么、不如、太……了: 跟上次考试相比，这次没有那么难. It is the spoken twin of 与……相比 (more written, hsk6-g15). Don't add 比 to it: the comparison is already in 相比.
Examples
姐姐大我三岁。
Jiějie dà wǒ sān suì.My older sister is three years older than me.
你高我五厘米，帮我拿一下上面的书吧。
Nǐ gāo wǒ wǔ límǐ, bāng wǒ ná yíxià shàngmiàn de shū ba.You're five centimetres taller than me: could you get that book from up there?
她早我两天到成都，已经找好房子了。
Tā zǎo wǒ liǎng tiān dào Chéngdū, yǐjīng zhǎo hǎo fángzi le.She got to Chengdu two days before me and has already found a place to live.
这份工作的工资高那份一千块，可是要经常加班。
Zhè fèn gōngzuò de gōngzī gāo nà fèn yì qiān kuài, kěshì yào jīngcháng jiābān.This job pays a thousand yuan more than the other one, but there is often overtime.
跟上次考试相比，这次没有那么难。
Gēn shàng cì kǎoshì xiāngbǐ, zhè cì méiyǒu nàme nán.Compared with the last exam, this one isn't as hard.
跟别人相比，我的想法太简单了。
Gēn biérén xiāngbǐ, wǒ de xiǎngfǎ tài jiǎndān le.Compared with other people's, my ideas are far too simple.
Common mistakes
✗ 她高比我五厘米 → ✓ 她比我高五厘米 / 她高我五厘米 (never 比 after the adjective; without 比, B follows the adjective directly).
✗ 这家店好吃那家一点儿 → ✓ 这家店比那家好吃一点儿 (without 比, only a measurable quantity: 大、小、高、重、长、早、晚).
✗ 跟别人相比，我的想法比简单 → ✓ 跟别人相比，我的想法太简单了 (相比 already holds the comparison: don't add 比, comment with 太、更、不如).