Daftar Pustaka https://studioliterasi.com/aritmatika-sosial/ https://www.orangbaik.org/contoh-soal-harga-beli-dan- jual/https://www.akuntansilengkap.com/akuntansi/10- contoh-pembelian-dan-penjualan-tunai-kredit-retur- potongan/