List of basic calculations
Evolution of the Hindu-Arabic digit
Brahmic numerals represented 1, 2, and 3 with as many lines. 4 was simplified by joining its four lines into a cross that looks like the modern plus sign. The Shunga would add a horizontal line on top of the digit, and the Kshatrapa and Pallava evolved the digit to a point where the speed of writing was a secondary concern. The Arabs 4 still had the early concept of the cross, but for the sake of efficiency, was made in one stroke by connecting the "western" end to the "northern" end; the "eastern" end was finished off with a curve. The Europeans dropped the finishing curve and gradually made the digit less cursive, ending up with a digit very close to the original Brahmin cross.While the shape of the character for the digit 4 has an ascender in most modern typefaces, in typefaces with text figures the glyph usually has a descender, as, for example, in . On the seven-segment displays of pocket calculators and digital watches, as well as certain optical character recognition fonts, 4 is seen with an open top.Television stations that operate on channel 4 have occasionally made use of another variation of the "open 4", with the open portion being on the side, rather than the top. This version resembles the Canadian Aboriginal syllabics letter ᔦ. The magnetic ink character recognition "CMC-7" font also uses this variety of "4".
Post-surgical: after frontal sinus reconstruction

Diagnosis
Diagnosis is suspected clinically and is confirmed using cross sectional imaging of the sinuses and brain. The patient typically presents with a headache overlying the frontal sinuses and an associated forehead swelling. This is often preceded by a history of chronic rhinosinusitis.Plain X Rays can be used to demonstrate the location of this swelling, but the gold standard for diagnosis is a cross sectional CT scan of the sinuses and brain, aided by contrast to delineate the abscess itself. Treatment
The patient requires admission for intravenous anti-microbial treatment. Definitively, the abscess is drained via a combination of open and/or endoscopic approaches by an otolaryngologist, with the exact approach dependent on surgical skill set. At the very least, the abscess is trephined externally as an emergency. Any associated frontal sinus table fracture can be managed electively. Intracranial extension requires referral to the neurosurgery. References
External links

Karaman E, Hacizade Y, Isildak H, Kaytaz A (2008). "Potts puffy tumor". J Craniofac Surg. 19 (6): 1694–7. doi:10.1097/SCS.0b013e31818b432e. PMID 19098585.