How to use the lisk-sdk.BigNum function in lisk-sdk

undoAsset(store) {
		const errors = super.undoAsset(store);

		const sender = store.account.get(this.senderId);
		const updatedSenderBalanceAfterBonus = new BigNum(sender.balance).sub(
			new BigNum(this.amount).div(10)
		);
		const updatedSender = {
			...sender,
			balance: updatedSenderBalanceAfterBonus.toString(),
		};
		store.account.set(sender.address, updatedSender);

		return errors;
	}
}

applyAsset(store) {
		const errors = super.applyAsset(store);

		const sender = store.account.get(this.senderId);
		const updatedSenderBalanceAfterBonus = new BigNum(sender.balance).add(
			new BigNum(this.amount).div(10)
		);
		const updatedSender = {
			...sender,
			balance: updatedSenderBalanceAfterBonus.toString(),
		};
		store.account.set(sender.address, updatedSender);

		return errors;
	}

undoAsset(store) {
		const errors = super.undoAsset(store);

		const sender = store.account.get(this.senderId);
		const updatedSenderBalanceAfterBonus = new BigNum(sender.balance).sub(
			new BigNum(this.amount).div(10)
		);
		const updatedSender = {
			...sender,
			balance: updatedSenderBalanceAfterBonus.toString(),
		};
		store.account.set(sender.address, updatedSender);

		return errors;
	}
}

applyAsset(store) {
		const errors = super.applyAsset(store);

		const sender = store.account.get(this.senderId);
		const updatedSenderBalanceAfterBonus = new BigNum(sender.balance).add(
			new BigNum(this.amount).div(10)
		);
		const updatedSender = {
			...sender,
			balance: updatedSenderBalanceAfterBonus.toString(),
		};
		store.account.set(sender.address, updatedSender);

		return errors;
	}