Making a number from clues

Earlier, we compared numbers place by place, starting from the thousands. Today, we use digit cards to make the greatest or smallest number that fits a clue. Use the digit cards 1, 5, 6, 8 once each. Make the greatest four-digit even number. If we put the greatest cards first, we get eight thousand, six hundred and fifty-one. But it ends in 1, so it is odd. An even number must have an even ones digit. The ones digit can be six or eight. Put six in the ones place first. The greatest card left is eight. The greatest card left is five. The greatest card left is one. Put eight in the ones place first. The greatest card left is six. The greatest card left is five. The greatest card left is one. Compare the thousands. 8 thousands is greater than 6 thousands. The greatest is eight thousand, five hundred and sixteen. It uses each card once, and it is an even number.

Use the digit cards 0, 1, 4, 6 once each. Make the smallest four-digit odd number. Try it first. Pause if you like. Only 1 is odd, so put 1 in the ones place first. Zero cannot go first, so the smallest card we can use is four. The smallest card left is zero. The smallest card left is six. The smallest is four thousand and sixty-one. It uses each card once, and it is an odd number.

Use the digit cards 2, 4, 7, 9 once each. Make the greatest four-digit odd number. Try it first. Pause if you like. An odd number must have an odd ones digit. The ones digit can be seven or nine. Put seven in the ones place first. The greatest card left is nine. The greatest card left is four. The greatest card left is two. Put nine in the ones place first. The greatest card left is seven. The greatest card left is four. The greatest card left is two. Compare the thousands. 9 thousands is greater than 7 thousands. The greatest is nine thousand, four hundred and twenty-seven. It uses each card once, and it is an odd number. Put a digit that fits the clue in the ones place first, then fill the other places from the thousands.