4. Insert commas suitably and write the names according to International System of Numeration:
(a) 78921092 (b) 7452283 (c) 99985102 (d) 48049831

(a) 78,921,092 – Seventy eight million nine hundred twenty one thousand ninety two
(b) 7,452,283 – Seven million four hundred fifty-two thousand two hundred eighty three
(c) 99,985,102 – Ninety-nine million nine hundred eighty five thousand one hundred two
(d) 48,049,831 – Forty-eight million forty-nine thousand eight hundred thirty-one