KARA NEEDS $35 FOR AN AQUARIUM FOR 6 FISH. HOW CAN SHE PAY WITH THE LEAST TEN AND ONE DOLLAR BILLS?

$20 bill + $10 bill + $5 bill.

$41

To determine the least number of ten and one dollar bills Kara needs to pay for the aquarium, we can approach this problem by using a division algorithm.

1. First, let's find the maximum number of ten-dollar bills Kara can use.
- Divide the total amount needed, which is $35, by the denomination of a ten-dollar bill, which is $10.
- 35 ÷ 10 = 3 remainder 5.
- This means that Kara can use a maximum of 3 ten-dollar bills, with a remaining amount of $5.

2. Next, let's see how many one-dollar bills Kara needs to cover the remaining amount.
- Since Kara has $5 remaining, we divide this amount by the denomination of a one-dollar bill, which is $1.
- 5 ÷ 1 = 5.
- This shows that Kara needs 5 one-dollar bills to cover the remaining $5.

Therefore, Kara needs 3 ten-dollar bills and 5 one-dollar bills to pay for the aquarium, with the least number of bills.