Kris Jenner says "one her biggest joys" in life is making her 13 grandchildren "happy"

She told 'E! News': "Dream just got training wheels off her bike a couple months ago.

"I bought her a new bike for her birthday. She was super excited and she went up from an 18-inch to a 20-inch."

She said of her grandchildren: "They're excited. They're growing up. They're loving new things.

"It's nice to see the [difference]. One year, they'll be into a certain type of doll, and then you clearly see that shift when it's the following Christmas, and now we're into something else, a little more mature."

The businesswoman loves to go all out for the children.

Kris added: "I think one of my biggest joys is when I do something to make them happy.

"Like, I'll decorate my whole house really wild for Halloween and do scary things in the backyard."

The momager is also grandmother to Kim Kardashian's four children, North, 11, Saint, nine, Chicago, six, and five-year-old Psalm, with ex-husband Kanye West, and Khloe Kardashian's daughter True, six, and son Tatum, two, whose father is basketball player Tristan Thompson.

As well as Kourtney Kardashian's four children, Mason, 14, Penelope, 12, and nine-year-old Reign, with ex-partner Scott Disick, and 13-month-old Rocky, with husband Travis Barker.

And Kylie Jenner's six-year-old Stormi and two-year-old Aire, whom she has with ex-partner Travis Scott.