4098+(1765+7908)=4098+9673=13771
7509+(12078+9067)=7509+21145=28654
15728+(4987+3751+7399)=15728+16137+31 865
10087+(3445+5684+7889)=10087+17018=27 105
7509+(12078+9067)=28654
15728+(4987+3751+7399)=31905
10087+(3445+5684+7889)=27106
4098+(1765+7908)=4098+9673=13771
7509+(12078+9067)=7509+21145=28654
15728+(4987+3751+7399)=15728+16137+31 865
10087+(3445+5684+7889)=10087+17018=27 105