qmk-dactyl-manuform-a/layouts/default/ortho_4x4/default_ortho_4x4/keymap.c

#include QMK_KEYBOARD_H

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
    /*
     * ┌───┬───┬───┬───┐
     * │ 7 │ 8 │ 9 │ / │
     * ├───┼───┼───┼───┤
     * │ 4 │ 5 │ 6 │ * │
     * ├───┼───┼───┼───┤
     * │ 1 │ 2 │ 3 │ - │
     * ├───┼───┼───┼───┤
     * │ 0 │ . │Ent│ + │
     * └───┴───┴───┴───┘
     */
    [0] = LAYOUT_ortho_4x4(
        KC_P7,   KC_P8,   KC_P9,   KC_PSLS,
        KC_P4,   KC_P5,   KC_P6,   KC_PAST,
        KC_P1,   KC_P2,   KC_P3,   KC_PMNS,
        KC_P0,   KC_PDOT, KC_PENT, KC_PPLS
    )
};