"It's a sense of accomplishment for them. Inactivity is one aspect of the challenges of parenting under Covid-19. You also worry about their ability to socialise and be resilient and you take steps to try and address it," says Mr Tan, who is married to housewife Shermin Pang.
The couple, both 38, also have a one-year-old son, Callum.
To bond with family members who do not live with them, the couple and their daughters arrange "family challenges" with Mr Tan's dad, vying to see who can clock the most steps in three days.
Granddad, who is 72, usually wins.
Ms Angelina Ong, 45, noticed that her children were listless yet restless when they had to stay in more.