1. Look for the possibilities you have. Don't forget, you need minimum two card sides (up to 4) next to the card you want to place on field. You can't attack with PLUS if only one card side would be attacked.
2. Build the differences for each possibility. In this case you have to place a card between the blue cards, or on the left/right side of the red card - which means.
- bottom/left: found 7 and 8; make the difference: 8 - 7 = 1
- right/top: found 9 and 4; make the difference: 9 - 4 = 5
- right/left: found 9 and 5; make the difference: 9 - 5 = 4
- left/top: found 5 and 4; make the difference: 5 - 4 = 1
- bottom/right: found 5 and 8; make the difference: 8 - 5 = 3
3. Now look for the differences you can calculate for opposite card-sides of your hand cards. You need to finde th same differences. In this case "Enno" will do, because there are two matches - top/right and right/bottom.
- top/right: found 3 and 2; make the difference: 3 - 2 = 1 > matches to same difference before bottom/left (8 - 7 = 1)
- right/bottom: found 2 and 3; make the difference: 3 - 2 = 1 > matches to same difference before left/top (5 - 4 = 1)
4. There are potential possibilities. You have to calculate now, if at least one of them has the same sum. If not, the PLUS attack will miss.
- top/right and bottom/left; add top with bottom and add right with left; 3 + 7 = 10 and 2 + 8 = 10; compare sum; 10 = 10; PLUS will work, if we place "Enno" on the left of the red card
- right/bottom and left/top; add right with left and add bottom with top; 2 + 5 = 7 and 3 + 4 = 7; compare sum; 7 = 7; PLUS will work, if we place "Enno" between the two blue cards
5. Place the card.
6. In this case "Enno" is placed on the left side of the red card in the center of the field
7. The PLUS attack changed the top left card (former blue) into red - your card, allthough the direct attack value of your card is weaker.
Note
- you can use your on cards (red) on the field for PLUS attack
- but only the enemy cards (blue) will be affected
- affected blue cards (now red) will get a bonus (+ 1) to all their values, which means the top left card has now 4, 10, 8, 3 (former: 3, 9, 7, 2)