function loopit_percentages() {
var percentcols = ['D', 'E','F']
for (var k = 0; k<= percentcols.length -1; k++) {
for (var i = 1; i<=20;i++) {
var rng = percentcols[k] + i.toString()
Logger.log(rng)
SpreadsheetApp.getActiveSheet().getRange(rng).setNumberFormat("0.00%")
}}}

function loopit_numbers() {
var percentcols = ['G', 'H']
for (var k = 0; k<= percentcols.length -1; k++) {
for (var i = 1; i<=20;i++) {
var rng = percentcols[k] + i.toString()
Logger.log(rng)
SpreadsheetApp.getActiveSheet().getRange(rng).setNumberFormat("0.00")
}}}

function run_all() {loopit_percentages()
loopit_numbers() }

run_all()