It is not always possible to take. If you cannot take, you try to build. A build is when a card from the hand is added to a single card, or combination of cards, from the centre. This creates a new number, ready for a later take.

Not being able to match the 9 for a take, you look to build.
Play the 1 from the hand, adding it to the 9, for a build of 10 (saying out loud, ’9 + 1 = 10′).
The build of 10 is valid, as you have the answer to the build in your hand in a single card. (It is recommended that players show the answer card to their opponent to prove the build is valid.)
Note: As you can play only one Number Card from your hand each turn, a build finishes your turn. You cannot take until your next turn. Restore your hand to five from the pack.
Any player may take a build if it is his/her turn.
A build may be added to by any player to make another build, provided they have the answer to the new build in a single card.
A build can never be broken up or separated.

Not being able to match the 5, the 3 or a combination of 5 and 3 (8) for a take, you look to build.
Play the 4 from the hand, adding it to the 5, for a build of 9 (saying out loud, ’5 + 4 = 9′);
or, play the 9 from the hand, adding it to the 3, for a build of 12 (saying out loud, ’9 + 3 = 12′);
or better still, combine the 5 and 3 from the centre to equal 8. Play 4 from the hand to the 8 for a build of 12 (saying out loud ’5 + 3 = 8, 8 + 4 = 12′).