Karabiner-Element config file for laptop keyboard with NumLock on. Put it at ~/.config/karabiner/karabiner.json

karabiner.json

{
    "global": {
        "check_for_updates_on_startup": true,
        "show_in_menu_bar": true,
        "show_profile_name_in_menu_bar": false
    },
    "profiles": [
        {
            "complex_modifications": {
                "parameters": {
                    "basic.simultaneous_threshold_milliseconds": 50,
                    "basic.to_delayed_action_delay_milliseconds": 500,
                    "basic.to_if_alone_timeout_milliseconds": 1000,
                    "basic.to_if_held_down_threshold_milliseconds": 500
                },
                "rules": []
            },
            "devices": [],
            "fn_function_keys": [
                {
                    "from": {
                        "key_code": "f1"
                    },
                    "to": {
                        "consumer_key_code": "display_brightness_decrement"
                    }
                },
                {
                    "from": {
                        "key_code": "f2"
                    },
                    "to": {
                        "consumer_key_code": "display_brightness_increment"
                    }
                },
                {
                    "from": {
                        "key_code": "f3"
                    },
                    "to": {
                        "key_code": "mission_control"
                    }
                },
                {
                    "from": {
                        "key_code": "f4"
                    },
                    "to": {
                        "key_code": "launchpad"
                    }
                },
                {
                    "from": {
                        "key_code": "f5"
                    },
                    "to": {
                        "key_code": "illumination_decrement"
                    }
                },
                {
                    "from": {
                        "key_code": "f6"
                    },
                    "to": {
                        "key_code": "illumination_increment"
                    }
                },
                {
                    "from": {
                        "key_code": "f7"
                    },
                    "to": {
                        "consumer_key_code": "rewind"
                    }
                },
                {
                    "from": {
                        "key_code": "f8"
                    },
                    "to": {
                        "consumer_key_code": "play_or_pause"
                    }
                },
                {
                    "from": {
                        "key_code": "f9"
                    },
                    "to": {
                        "consumer_key_code": "fastforward"
                    }
                },
                {
                    "from": {
                        "key_code": "f10"
                    },
                    "to": {
                        "consumer_key_code": "mute"
                    }
                },
                {
                    "from": {
                        "key_code": "f11"
                    },
                    "to": {
                        "consumer_key_code": "volume_decrement"
                    }
                },
                {
                    "from": {
                        "key_code": "f12"
                    },
                    "to": {
                        "consumer_key_code": "volume_increment"
                    }
                }
            ],
            "name": "Default profile",
            "selected": true,
            "simple_modifications": [
                {
                    "from": {
                        "key_code": "keypad_0"
                    },
                    "to": {
                        "key_code": "m"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_1"
                    },
                    "to": {
                        "key_code": "j"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_2"
                    },
                    "to": {
                        "key_code": "k"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_3"
                    },
                    "to": {
                        "key_code": "l"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_4"
                    },
                    "to": {
                        "key_code": "u"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_5"
                    },
                    "to": {
                        "key_code": "i"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_6"
                    },
                    "to": {
                        "key_code": "o"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_7"
                    },
                    "to": {
                        "key_code": "7"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_8"
                    },
                    "to": {
                        "key_code": "8"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_9"
                    },
                    "to": {
                        "key_code": "9"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_asterisk"
                    },
                    "to": {
                        "key_code": "0"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_hyphen"
                    },
                    "to": {
                        "key_code": "p"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_period"
                    },
                    "to": {
                        "key_code": "period"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_plus"
                    },
                    "to": {
                        "key_code": "semicolon"
                    }
                },
                {
                    "from": {
                        "key_code": "keypad_slash"
                    },
                    "to": {
                        "key_code": "slash"
                    }
                },
                {
                    "from": {
                        "key_code": "right_control"
                    },
                    "to": {
                        "key_code": "right_command"
                    }
                }
            ],
            "virtual_hid_keyboard": {
                "country_code": 0
            }
        }
    ]
}

https://github.com/tekezo/Karabiner-Elements